delivered the Oplmon of the Court.
{ 1 We accepted jurisdiction over this certified question of law from the United States Court of Appeals for the Tenth Cireuit,. See CAR, 21.1. The Tenth Cireuit has asked us whether the City of Englewood's Ordinance 84, which effectively bars certain sex offenders from residing within the city, is preempted by Colorado law. 560 Fed.Appx. 726 (10th Cir.2014) (unpublished order), ~As a preliminary matter, we conclude that because both state and local governments bave an interest in governing the matter of sex offender residency, the ordinance concerns an issue of mixed state and local concern. As such, it may stand as long as it does not conflict with state law on the subject: Webb v. City of Black Hawk, 2013 CO 9, ¶ 16, 295 P.3d 480, 486. The federal district court in this case concluded that such a conflict did exist because Colorado has generally opted for a policy of individualized treatment of sex offenders, and the Englewood ordinance acts as an effective bar to residency. Ryals v. City of Englewood, 962 F.Supp2d 1236, 1249-51 (D.Colo.2013). We disagree with the federal district court and find no conflict. There is no state law that requires individual consideration with regard to the residency of sex offenders, and in fact state law and the ordinance may both be given full effect. Because we conclude that no conflict exists between state law and the ordinance, Ordinance 84 is not preempted by state law. We therefore answer the certified question in the negative and return this case to the Tenth Ciretit for further proceedings.
1.
12 In 2001, Stephen Brett Ryals had a sexual relationship with a sixteen-year-old girl he coached on a high school soccer team. He pled guilty to criminal attempt to commit sexual assault on a child by one in a position of trust -and was sentenced to seven years of probation. After violating his probation by continuing to see the victim, he was sentenced to two years in prison, He was released in April of 2008. Under the Colorado Sex Offender Registration Act (FCSORA"), §§ 16-22-101 to -115, C.R.S. (2015), he was required to register as a sex offender for a decade after his release. $ 16-22-108(1)(a). He is under no other state supervision.
18 In July of 2006, the Colorado Parole Board informed the City of Englewood, a home-rule municipality, that it 'planned" to place a sexually violent predator at an extended-stay hotel that was within a block of a daycare facility. Originally, the placement was planned in Greenwood Village, but Greenwood Village passed a local ordinance that essentially banned sex offenders from residing in the city. In response, Englewood passed its own emergency ordinance in Sep*904tember 2006 that operated in the same way, effectively barring sex offenders from residing in the city.
T4 The ordinance applies generally in two instances. - First, it applies to sexually violent predators as defined by section 18-8-414.5, C.R.S. (2015). Second, it applies to those sex offenders who, like Ryals, are required to register under CSORA because they have either been "[clonviected of a felony for an offense requiring registration," have "multiple convictions for offenses requiring registration," or their "offense(s) requiring registration involved multiple victims." EMC 7-3-3(A)Gi)a-b.
15 The ordinance makes it unlawful for people in either group to "establish a permanent residence or temporary residence within two thousand feet (2,000°) of any school, park, or playground or within one thousand feet (1,000) of any licensed day care center, recreation center or swimming pool (other than pools located at private, single-family residences)" EMC 7-3-8(A) According to estimates, these restrictions make 99% of the city off limits to qualifying sex offenders. Ryals, 962 F.Supp.2d at 1241.
T6 The stated intent of the ordinance is "to serve the City's compelling interest to promote, protect and improve the public health, safety and welfare by creating areas, around locations where children regularly congregate in concentrated numbers, where sexual predators and specified sexual offenders are prohibited from establishing temporary or permanent residence." EMC 7-8-1.
T7 In 2012, Ryals purchased a home in Englewood. After buying the home, he called the local police to ask about the process of registering as a sex offender, An officer told him that, because he was a qualifying sex offender under Englewood's Ordinance 34, he was not allowed to live within the city limits. Nevertheless, Ryals went to the Englewood police station the next day to attempt to register. He was issued a citation for violating the ordinance.
T8 He then sued Englewood in the U.S. District Court for the District of Colorado, asserting, among other claims, that Ordinance 84 is preempted by Colorado's sex offender regulations. The criminal proceeding against him stemming from the citation was stayed while he challenged the validity of the ordinance.
T9 The federal district court held that the ordinance was preempted by Colorado state law. First, the court concluded that the ordinance addressed a matter of mixed state and local concern because it implicated both local and state interests, - Ryals, 962 F.Supp.2d at 1249 (finding that the city has a valid interest in regulating land use and protecting its citizens but that the ordinance implicated "substantial state interests," including "the consistent application of statewide laws to fulfill the goal of managing and supervising sex offenders"). It then concluded that, in its operation, Ordinance 34 conflicted with the state's comprehensive regime for regulating sex offenders and therefore was preempted by state law. Id. It reasoned that the state had adopted an individualized approach to sex offender treatment, and that the ordinance conflicted with such an individualized approach because it did not, on an offender-by-offender basis, consider "the nature of the offense, the treatment the offender has received, the risk that he or she will reoffend against children, and the evaluation and recommendations of qualified state officials" when determining whether a sex offender could reside Wlthm the city. Id. at 1251.
10 Englewood appealed the ruling to the Tenth Cireuit. The circuit court determined that "every step of [the issue's] resolution is firmly within the province of Colorado law" and certified the question to this Court under Tenth Cireuit Rule 27.1 and C.A.R. 21.1. 560 Fed.Appx. at 729.
IL
111 To determine i#f state law preempts a home-rule city's ordinance, we engage in a two-step analysis. See Webb, ¶¶ 16, 43, 295 P.3d at 486, 492, First, we ask whether the issue the ordinance regulates is one of local, statewide, or mixed local and statewide concern. Id. at ¶ 16, 295 P.3d at 486. If we conclude that the issue is of mixed concern, as we do here, we then ask whether the ordinance conflicts with state *905law on that issue. Id. at ¶ 43, 295 P.8d at 492. We conclude that Ordinance 34 does not conflict with any provision of state law. Therefore, it is not preempted.
A.
112 Colorado's preemption doe-trine begins with Article XX, section 6 of the Colorado Constitution, which grants municipalities "home rule" authority to govern "local and municipal matters." Colo. Const. art XX, § 6. In order to determine the boundaries of state authority vis-a-vis the authority of a home-rule municipality, we have developed three categories into which a specific issue may fall: (1) matters of local concern, (2) matters of statewide concern, and (8) mixed matters of state and local concern. Webb, ¶ 18, 295 P.3d at 486. Both the home-rule city and the state may legislate with regard to matters of local concern, but in the event of a conflict, the home-rule provision prevails over the state provision, Id. In matters of statewide concern, the state legislature has plenary authority, and the home-rule city has no power to act unless the constitution or a state statute specifically affords it such power, Id. For matters of mixed state and local concern, both the home-rule city and the state may regulate, so long as the regulations do not conflict. Id. In the event of a conflict, the state law preempts and supersedes the local provision. Id. Consequently, to determine whether state law preempts a local law under Article XX, section 6, we must first ask whether the regulated matter is one of local, state, or mixed local and state concern. We have held that such a determination is a legal question. Id. at ¶ 19, 295 P.3d at 486.
113 We make this determination on a case-by-case basis, considering the relative interests of the state and the municipality in regulating the matter. Id. Although we may consider any factors we deem relevant, we have consistently consulted four factors in making this determination: (1) the need for statewide uniformity; (2) the extraterritorial impact of the regulation at issue; (8) whether the matter has traditionally been regulated at the state or local level; and (4) whether the Colorado Constitution commits the matter to state or local regulation. Id. As a practical matter, it is rare for a matter to "fit neatly within one of thle] three categories." Id. Before considering the four factors, we briefly describe the state's sex offender regulations. | ~
B.
114 Colorado's sex offender scheme has three main features relevant to our analysis: management of sex offenders by the Sex Offender Management Board ("SOMB"), sex offender registration under CSORA, and parole board supervision of offenders on supervised release or subject to the Colorado Sex Offender Lifetime. Supervision Act of 1998 ("SOLSA").
T 15 In 1992, the Colorado General Assembly created the SOMB "to protect the public and to work toward the elimination of sexual offenses." § 16-11.7-101(1), C.R.S. (2015). It tasked the SOMB to "comprehensively evaluate, identify, treat, manage, and monitor adult sex offenders who are subject to the supervision of the eriminal justice system" by establishing "evidence-based standards for the evaluation, identification, treatment, management, and monitoring of adult sex offenders." §§ 16-11.7-101(1), (2).
1 16 One of the SOMB's duties is to determine the "best practices for living arrangements for and the location of adult sex of fenders within the community." § 16-11.7-108(4)(g), C.R.S. (2015). Another is to "develop, implement, and revise, as appropriate, guidelines and standards to treat adult sex offenders." § 16-11.7-108(4)(b). The SOMB does this by publishing its "Standards and Guidelines for the Assessment, Evaluation, Treatment and Behavioral Monitoring of Adult Sex Offenders" Only one of these guidelines directly pertains to sex offender residency, providing that, when a sex offender seeks to change residences, "any change of residence must receive prior approval by the supervising officer" Standards and Guidelines § 5.620(K) (2011).
117 At the request of the General Assembly, the SOMB drafted a paper called "Report on Safety Issues Raised by Living Arrangements for and. Location of Sex Of*906fenders in the: Community." In the report, the SOMB examined residency restrictions such as the one in Englewood, found that they are counterproductive to public safety, and recommended against them,. While this report is "vital to inform the decisions" of the - General - Assembly, § 16-11,7-109, CRS. (2015), it is not itself binding law, and the General Assembly has taken no legislative action in response to it. On the contrary, the legislature rejected a 2006 attempt to adopt a statewide residency standard.
[ 18 The second chief feature of Colorado's sex offender regulatory regime, CSORA, requires adults convicted of certain sex crimes to register with local law enforcement in the jurisdiction where they live, § 16-22% 108(1)(a)(I), C.R.S. (2015); see also § 16-22-108. Local law enforcement is responsible for approving and verifying registrants addresses. § 16-22-109(8.5)(a).
119 In deciding whether to accept an offender's registration, law enforcement officials may account for local residence ordinances under CSORA,. Specifically, the statute provides that a "law enforcement agency is not required to accept [a] person's registration if it includes a residence ... that would violate state law or local ordinance." § 16-22-108(1)(a)(D). '
~T 20 The regulatory scheme's final feature, SOLSA, regulates the state's supervision of sex offender's in conjunction with the parole process,. See § 18-1.31005, C.R.S. (2015). The only provision from this statute that deals with sex offender residency provides that "the division of adult parole shall provide parole supervision and assistance in securing employment, housing, and such other services as may effect [sic] the successful reintegration of such offender into the community while recognizing the need for public safety." § 17-22.5-408, CRS. (2015)... In practice, this means that, when a sex offender relocates, he or she is responsible for finding the residence, and the officer approves it. We now turn to the factors.
C.,
«1.
- T21 First, we address the need for uniformity in the area of-sex offender regulation. Although "uniformity in and of itself is not a virtue .;. in the appropriate case the need for uniformity in. the operation of the law may be a sufficient basis for [state] legislative preemption." City of Commerce City v. State, 40 P.3d 1273, 1280 (Colo.2002) (alteration in original) (citations omitted). A need for uniformity exists "when it achieves and maintains specific state goals." City of Northglenn v. Ibarra, 62 P.3d 151, 160 (Colo.2003).
1 22 The strongest indication of a need for uniformity in the area of sex offender residency derives from the legislature's creation of the SOMB. The General Assembly has determined that, "to protect the public and to work toward the elimination of sexual offenses, it is necessary to comprehensively evaluate, identify, treat, manage, and monitor adult sex offenders." § 16-11.7-101(1) (emphasis added). It has also acknowledged a need to create and enforce "evidence-based standards for the evaluation, identification, treatment, management, and monitoring of adult sex offenders." § 16-11.7-101(@). To these ends, it created the SOMB to promul< gate statewide standards for sex offender management. - See § 16-11.7-108(4). In Ibarra, 62 P.3d at 160, we concluded that the need for uniformity was strong in the context of juvenile sex offenders who were also adjudicated delinquent and placed in foster care homes. While nothing in the statute explicitly states that regulations regarding adult sex offender residency must be uniform,, the state's interest in ensuring that such offenders "can rely on consistent procedures and practices designed to rehabilitate them" mirrors the state interest in TZhoarra. Id. at 161.
T 23 Furthermore, the statute instructs the. SOMB to "research, analyze, and make ree ommendations that reflect best practices for [adult sex offenders'] living, arrangements." § 16-11.7-108(g) (emphasis added). It must also "adopt and revise as appropriate such guidelines as it may deem appropriate regarding the living arrangements and location of adult sex offenders," presumably consistent with these "best practices," Id. The legislature's command that the SOMB identi*907fy and issue regulations that reflect the "best practices" with respect to living arrangements suggests a need for uniformity in this more specific aspect of sex offender management. ©
124 Aside from this provision regarding "best practices," however, Colorado law does not explicitly address the more specific issue of residency. While 'the SOMB's position paper argues against residency restrictions, that paper is merely advisory in nature. See § 16-11.7-109 (stating that the SOMB's "research and analysis of treatment standards and programs ... is vital to inform the decisions" of the General Assembly). It is not itself binding law, and the General Assembly has taken no legislative action in response to it. Moreover, the only "best practice" the SOMB has promulgated pursuant to section 16-11.7-108(g) simply, requires officer approval of a new residence before an offender moves in. See Standards and Guidelines § 5,620(K).
125 Significantly, state law envisions at least some role for local governments in the regulation of sex offender residency. CSORA specifically provides that local law enforcement officers need not approve an offender's registration "if it includes a residence or location that would violate state law or local ordinance." § 16-22-108(1)(a)(I) (emphasis added). This language suggests that although there is a need for uniformity in the more general area of sex offender management, there is room for difference in the narrower area of residency regulation.
2.
126 The second factor is "the impact of municipal regulation on persons living outside the municipal limits" - Commerce City, 40 P.Sd at 1280. Concerns involving such extraterritorial impacts necessarily implicate "the expectations of state ... residents" in other localities. Fraternal Order of Police, Colorado Lodge No. 27 v. City & Cty. of Denver, 926 P.2d 582, 590 (Colo.1996). For an ordinance to create an extraterritorial impact, it "must have serious consequences to residents outside the municipality, and be more than incidental or de minimus." Ibarra, 62 P.3d at 161. In Ibarra, for instance, we found that an ordinance limiting the number of juvenile sex offenders who could reside in 4 single foster home created an extraterritorial impact because it decreased the number of homes available in the strained statewide system. Id. > >
T27 Her, the ordinance could producé impacts beyond Englewood's borders. First, just as the ordinance in Ibarra would reduce the number of homes available for juvenile sex offenders, so too would Ordinance 34 limit the number of cities available for adults. Relatedly, the ordinance forees sex.offenders who would prefer to live in Englewood to live elsewhere, thereby increasing the number of sex offenders in other municipalities.
128 Finally, restrictions such as Engle-wood's could potentially create a "domino effect," where other cities set up similar restrictions to prevent would-be Englewood residents from relocating to them. This is precisely why Englewood passed Ordinance 34 in the first place-as a response to the passage of a similar restriction in Greenwood Village,. In the. past;, we have found that such "domino effects" indicate that a matter is of statewide or mixed concern. See Webb, ¶ 37, 295 P.3d at 491 (noting that Black Hawk's ban on bicycles could "lead to other municipal bicycle bans by local communities which, like Black Hawk, would like to favor large transportation coachés over bicycles").
11 29 It is important, however, not to overstate this concern over the "domino effect" with regard to ordinances similar to the one at issue here. Restrictions like Englewood's have been in effect for years, yet the state has not seen a dramatic influx in them that would threaten to preclude sex offenders from residing in Colorado. Instead, the record indicates that only six cities have implemented such . restrictions.. . Ryals, 962 F.Supp.2d at 1247 n.6 (listing five cities in addition to.. Englewood that have adopted similar ordinances).
8.
1130 With respect to the third factor, we ask whether sex offender residency is a matter which has traditionally been regulat*908ed by the state or by the home-rule city. In making this determination, the court has rejected. a "categorical approach". and has instead "focused on the importance of the facts and cireumstances of the particular case to determine the status of the matter at issue, including the time, technology, and economics." Webb, ¶ 38, 295 P.3d at 491 (citations omitted).
€31 Here, this factor cuts in both directions. -On the one hand, over the past two decades, the state has regulated many aspects of sex offender management through organizations like the SOMB. At the same time, however, Ordinance 34 is a zoning ordinance that regulates land use, an area traditionally of local concern, While this is a compelling consideration in favor of the city, it does not require us to find that residency is a local matter, See Ibarra, 62 P.3d at 162 (rejecting . "categorical" - classifications of land-use ordinances as primarily local in nature).
4.
$32 The final enumerated factor is whether the Colorado Constitution commits the regulation of sex offender residency to either the state or local governments. Here, this factor does not clearly favor one side over the other.
183 Ryals argues that, because the legal status of sex offenders flows from the state judiciary, the issue of their placement is a state issue. In Ibarra, we made a similar observation, noting that "the legal status of [juvenile sex offenders] flows directly from the judicial powers granted exclusively to state courts under Article VI of the Colorado Constitution." Id. Ryals's argument is not persuasive in this context, however. In Ibar-ra, both the judiciary and the state played an active role in the placement of delinquent children, Id. at 157. Here, by contrast, any judicial role is too attenuated to make the Article VI argument made in Ibarra. Moreover, there is no state statute to provide specific guidance on residency for sex offenders in this situation.
' 34 Englewood's argument is equally unavailing. -It argues that the Colorado Constitution assigns its power to regulate in this area based on the home-rule amendment. This argument, however, reads the home-rule amendment too broadly, as a city's mere power to regulate "does not necessarily mean that the [regulated] matter is a strictly local issue." Commerce City, 40 P.3d at 1284.
135 As such, we find that the Colorado Constitution specifically commits the issue of sex offender residency to neither the state nor local government.
5.
136 Besides the four factors we have traditionally consulted, two additional factors are relevant to this case. The first is the degree of cooperation required between state and local governments for state sex offender regulations. Ibarra, 62 P.3d at 162-63. The more cooperation required between the two entities, the more likely we are to find the matter to be of statewide or mixed concern. Id. at 162 (citing City & Cty. of Denver v. State, 788 P.2d 764, 767 (Colo.1990)). In Ibarra, we found that the placement of juveniles in foster care homes required significant cooperation because the state was required to work with local social services offices to "place them in the most appropriate setting available consistent with the needs of the child and the community." Id. at 163.
T37 Here, the placement of sex offenders requires similar cooperation between state and local governments, as local law enforcement is charged with registering sex offenders and approving their residencies. § 16-22-108(1)(a)(I). As local officials may decline to accept registrations that violate local law, id., however, the degree of local cooperation required is not as stringent as it was in Ibarra.
138 The final factor is legislative declarations on the issue. See Webb, ¶ 19, 295 P.3d at 486 ("Although not conclusive in itself, a determination by the General Assembly that a matter is of statewide concern is relevant."). Here, the state, in its creation of the SOMB, has emphasized that "it is necessary [for public safety] to comprehensively evaluate, identify, treat, manage, and monitor adult sex offenders." § 16-11.7-101(1) (em*909phasis added). While this does not amount to an explicit statement. that sex offender residency is a matter of statewide concern, it does indicate that the broader area encompassing this specific issue-the management of sex offenders-is of such concern,
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189 As in most cases, the issue of sex offender residency is not given to easy categorization. Most prominent among the state's interests are its interests in the uniform application of sex offender laws in general and in preventing the potentially significant extraterritorial impacts the Englewood ordinance may produce. At the same time, Englewood has interests in protecting its community and in controlling local land use, an area traditionally left to local governments. Furthermore, the statute specifically contemplates deferring to local governments in some contexts. Importantly, the history of sex offender regulation and the degree of cooperation required between state and local government in this area suggest that both sides have a stake in the matter of sex offender residency.
{ 40 We thus conclude that the issue of sex offender residency implicates both state and local interests. Consequently, we agree with the federal district court that this is an issue of mixed state and local concern.
D.
141 Having found that sex offender residency is a mixed matter, we next ask whether Ordinance 84 conflicts with state law. Webb, ¶ 43, 295 P.3d at. 492. To address this issue, we have asked "whether the home-rule city's ordinance authorizes what [a] state statute forbids, or forbids what [a] state statute authorizes." Id.
T42 Turning to Ordinance 34, we find no conflict with state law. There is nothing in Colorado's sex offender regulatory regime that prevents home-rule cities from banning sex offenders from residing within city limits, nor is there anything that suggests that sex offenders are permitted to live anywhere they wish. Significantly, there is only one state provision that explicitly concerns sex offender residency, and that provision only requires state officers to approve sex offenders' new residences, Standards and Guidelines § 5.620(K). Nothing in this provision suggests that a city cannot ban sex offenders from residing within its borders. State approval of a sex offender's application does not imply that a city must also approve it,. On the contrary, state approval is but one prerequisite to relocating. Once an offender obtains this approval, he or she still must register with local law enforcement, which may decline the registration if the new residence violates local law." See § 16-22-108(1)(a)(I) (stating that a "law enforcement agency is not required to accept [a] person's registration if it includes a residence ... that would violate state law or local ordinance") {emphasis added). Thus, state law on the subject of sex offender registry recognizes that local ordinances play an important role in determining residency.
43 Ryals argues that state law "authorizes" him to live wherever he chooses within the state because no state statute deals with sex offender residency. This argument is unpersuasive. "Authorization" _- requires more than legislative silence on an issue. The failure or refusal to prohibit an action does not amount to "authorization" of that action. See Vela v. People, 174 Colo. 465, 484 P.2d 1204, 1206 (1971) (concluding that a state statute that failed to include the use of profane language in public as a form of disturbing the peace did not authorize citizens to use profane language in public). If legislative silence amounted to authorization, then it would be virtually impossible for local governments to restrict anything. Ryals's argument thus goes too far. Furthermore, in this case, we have no reason to read legislative silence as implied authorization for sex offenders to live wherever they please. Indeed, the SOMB submitted a report to the General Assembly criticizing ordinances like Englewood's, and the legislature took no action in response to it,
1] 44 For its part, the federal district court found a conflict by reading requirements into the statutory scheme that are simply not there. Citing sections 16-11.7-101, 16-11.7-109(1)(a), and 16-11.7-108(4)(g), the district *910court concluded that "the Colorado General Assembly has made clear its desire to promulgate a comprehensive system for regulating sex offenders that is based on individualized, evidence-based assessments." Ryals, 962 F.Supp.2d at 1249. In effect, the court inferred that, because the statutory scheme generally favors individualized assessments with regard to treatment, any local law lacking such individualized assessments conflicts with state law. But nothing in the provisions cited by the district court suggests that a home-rule city. must individually assess each sex offender seeking to reside within the city. Again, as noted above, the statute specifically provides that local officers are "not required to accept [a sex offender's] registration if it includes a residence ... that would violate ... [a] local ordinance." $ 16-22-108(1)(a)(D). Moreover, this provision contains no qualification on the types of local ordinances to be given effect and certainly does not suggest that local ordinances are effective only if they adopt an individualized assessment of a sex offender's possible residency. Contrary to the district court's conclusion, then, the fact that the state scheme favors individual assessments in general does not mean that a local law that lacks them conflicts with state law.
T 45 The district court also found it significant that, unlike Ordinance 84, some state provisions require officials to consider whether "the offender is appropriate for release from supervision and reintegration into the community." Ryals, 962 F.Supp.2d at 1250 (citing §§ 17-22.5-403(6), -403(8); § 18-1.3-1001, C.R.S. (2015)). For the district court, Englewood's ordinance "pose[s] a potentially substantial obstruction to ... reintegration goals" embodied in these provisions, Id. at 1251 {emphasis added). Similarly, the court concluded that "[the blacking out of entire cities to the placement of sex offenders potentially ereates a substantial burden on state probation and parole officers" charged with placement of offenders. Id. (emphasis added). In short, the court found that a potential conflict was sufficient for the 'state scheme to preempt the ordinance. But our test for conflict does not suggest that any potential for conflict must be deemed a conflict. State law and home-rule ordinances conflict where they "cannot coexist" and are "irreconcilable." Ray v. City & Cty. of Denver, 109 Colo. 74, 121 P.2d 886, 888 (1942). This is not the case with regard to Ordinance 34; therefore, there is no conflict.
ok
T46 Ultimately, we conclude that although sex offender residency is a matter of mixed state and local concern, there is no conflict between state law and Englewood's Ordinance 34. Accordingly, the ordinance is not preempted by state law.
IIL.
147 Because we conclude that Ordinance 34 is not preempted by state law, we answer the certified question from the Tenth Cireuit in the negative. We return this case to that court for further proceedings.
JUSTICE HOOD concurs in part and dissents in part, and JUSTICE GABRIEL joins in the concurrence in part and dissent in part. ‘