In this mandamus proceeding, three consolidated cases present the following question: Whether the judge-disqualification statutes, as amended by Oregon Laws 1987, chapter 338, constitute undue legislative interference with the judiciary?
The judge-disqualification statutes are codified in ORS 14.210 to 14.270. Of these statutes, only two are at issue: ORS 14.250 and 14.260(1).
ORS 14.250 provides for disqualifying a circuit court judge when it is established that “any party or attorney believes that such party or attorney cannot have a fair and impartial trial or hearing before such judge.”
ORS 14.260(1) then prescribes the procedure for establishing the belief that a fair and impartial trial or hearing cannot be had. It provides:
“Any party to or any attorney appearing in any cause, matter or proceeding in a circuit court may establish the belief described in ORS 14.250 by motion supported by affidavit that such party or attorney believes that such party or attorney cannot have a fair and impartial trial or hearing before such judge, and that it is made in good faith and not for the purpose of delay. No specific grounds for the belief need be alleged. Such motion shall be allowed unless the judge moved against, or the presiding judge in those counties where there is one, challenges the good faith of the affiant and sets forth the basis of such challenge. In the event of such challenge, a hearing shall be held before a disinterested judge. The burden of proof shall be on the challenging judge to establish that the motion was made in bad faith or for the purpose of delay.”
In each of these cases, the individual relators moved to disqualify the same circuit court judge. Relators and their attorney alleged that fair and impartial trials could not be had before the judge because the judge was “prejudiced” against the attorney. Defendant presiding judge1 denied the motions without hearings, concluding that ORS 14.250 and 14.260(1) *614violate the state constitution. Relators then sought peremptory writs or alternative writs of mandamus from this court directing defendant either to grant the motions or to grant them hearings on the “good faith” of the attorney.
Defendant chose not to oppose the petitions, requesting only the opportunity to respond once the writs were granted. We granted relators’ petitions for the alternative writs in all three cases. Defendant then moved to dismiss the writs.
This proceeding is a sequel to our earlier decision in State ex rel Oliver v. Crookham, 302 Or 533, 731 P2d 1018 (1987). In that decision, we construed several key provisions of the predecessor statutes to present ORS 14.250 and 14.260(1) while upholding the statutes as constitutional. In response, the legislature amended ORS 14.250 and 14.260(1). Or Laws 1987, ch 338. Those amendments changed the statutes in three significant ways.
First, the legislature eliminated the requirement, first stated in Oliver, for the affiant to allege “circumstances” leading to the belief that a fair and impartial trial cannot be had before the challenged judge. Compare State ex rel Oliver v. Crookham, supra, 302 Or at 541-42 with Or Laws 1987, ch 338, § 2 and ORS 14.260(1). Second, the legislature struck the requirement for alleging that the challenged judge was “prejudiced”; henceforth, the affidavit may allege solely the belief that a “fair and impartial trial or hearing” cannot be had before the challenged judge. Or Laws 1987, ch 338. Third, the legislature shifted the burden of proof onto the challenged judge to prove bad faith at the hearing requested by the judge questioning the affiant’s good faith. Previously, the burden had been upon the affiant to prove that the motion to disqualify the judge was made in good faith and not for purposes of delay. Compare State ex rel Lovell v. Weiss, 250 Or 252, 430 P2d 357, 442 P2d 241 (1968) with Or Laws 1987, ch 338, § 2.
Defendant contends that these changes constitute undue legislative interference with the judiciary. Defendant thus raises the question whether the legislation prevents the circuit courts from performing the judicial function assigned to them under Article VII (Amended), section 1, of the Oregon *615Constitution.2 See Circuit Court v. AFSCME, 295 Or 542, 547, 669 P2d 314 (1983). As we stated in that case:
“There can be no question that the legislature may enact laws prescribing the exercise of judicial powers. ‘The rule has evolved that legislation can affect [the courts] so long as it does not unduly burden or substantially interfere with the judiciary.’ * * * Most of the court’s activity is regulated by statute. Almost all of Title I of the Oregon Revised Statutes is devoted to this subject. * * * The article VII, section 1 concern is whether the challenged legislation * * * interferes with the judiciary in a manner which prevents or obstructs the performance of its irreducible constitutional task, adjudication.” 295 Or at 549. (Citations omitted.)
We turn to consider whether the three changes effected by the legislature’s 1987 amendments of ORS 14.250 and 14.260(1) constitute undue legislative interference with the judiciary’s “irreducible constitutional task, adjudication.”
1. Contents of the Affidavit.
Until our decision in State ex rel Oliver v. Crookham, supra, affiants could, and did, file affidavits alleging in barest terms the prejudice of the challenged judge. See U’Ren v. Bagley, 118 Or 77, 245 P 1074 (1926); Staff, Disqualification of Judges for Prejudice or Bias — Common Law Evolution, Current Status, and The Oregon Experience, 48 Or L Rev 311, 396-97 (1969). For instance, the affidavit in U’Ren alleged nothing further than that the attorney believed the judge to be “so prejudiced against me that I cannot, and I verily believe I cannot, have a fair and/or impartial trial of said cause before said judge.” U’Ren v. Bagley, supra, 118 Or at 80. One of the affidavits filed in these proceedings alleges the inability to obtain a fair and impartial trial in similar terms.3 The ques*616tion is whether Oliver articulated a standard rendering such affidavits constitutionally insufficient.
Simply put, Oliver did not. In Oliver, we did state that affidavits, to be “sufficient,” had to allege “circumstances which would permit a party or attorney reasonably to believe that the party or attorney will not receive a fair trial.” State ex rel Oliver v. Crookham, supra, 302 Or at 542. When we made that statement, however, we had in mind practical, not constitutional, concerns. We reasoned that this standard would render good faith hearings either shorter or wholly unnecessary because the basis for seeking disqualification would be known to the challenged judge at the outset. Id. at 541.
As a matter of constitutional law, however, we cannot conclude that ORS 14.260(1) falls short for permitting what might be termed “conclusory” affidavits. Such affidavits fall squarely within the bounds of the holding of this court in U’Ren v. Bagley, supra. In that case, as here, the court confronted statutes that do not require allegations of “circumstances” leading to the belief that a fair and impartial trial cannot be had. Amended ORS 14.260(1) explicitly does not require an allegation of “specific grounds” or circumstances, whereas Section 45-2, Oregon Laws, as amended by chapter 143 of General Laws of Oregon for 19254 (the statute before *617the U’Ren court) implicitly did not require such an allegation. We upheld Section 45-2 against constitutional attack in U’Ren. U’Ren v. Bagley, supra, 118 Or at 87. Discerning no reason to deviate from that precedent, we uphold ORS 14.260(1) here.
2. “Prejudice” vs. “Fair and Impartial Trial.”
Formerly, affiants had to allege that the challenged judge was “prejudiced” to disqualify that judge; that no longer is required. 306 Or at 614. As Oliver should make clear, however, the legislative tailoring does not tear the statutory garment.
Indeed, the amendment weaves a seamless pattern with what we did state about “prejudice” in our recent decision. In substance, we stated in Oliver that the key inquiry is whether a fair and impartial trial may be had before the challenged judge. See State ex rel Oliver v. Crookham, supra, 302 Or at 540. A fair and impartial trial may not be had when the challenged judge is partial for or against one of the parties or attorneys, i.e., when the challenged judge is “prejudiced.” See id. See also State ex rel Bowman v. Crookham, 302 Or 544, 547, 731 P2d 1025 (1987). In dropping the requirement to allege “prejudice” but retaining what is key, the legislature may have intended to “neutralize” the potential for inflamed feelings attendant when anyone, including a judge, is taken to task for being prejudiced.
3. Burden of Proof at Good Faith Hearing.
An allegation of good faith (and that the affidavit was not made for purposes of delay) was not required by the first judge-disqualification statutes. See Or Laws 1919, ch 160. We never have held that an allegation of good faith is a constitutional requirement of a motion and affidavit to disqualify a judge. See Foster v. Zeiler, 283 Or 255, 257, 584 P2d 243 (1978). But see State ex rel Lovell v. Weiss, supra, 250 Or at 255-56 (hearing into good faith required for statute to be constitutional). We have held that the legislature may not confer peremptory powers to disqualify circuit court judges, State ex rel Bushman v. Vandenberg, 203 Or 326, 276 P2d 432, 280 P2d 344 (1955), a conclusion whose continuing validity is not before us. But cf. State ex rel Oliver v. Crookham, supra, 302 Or *618at 538 (constitutional doubts expressed in Bushman not necessarily adhered to); State v. Holmes, 106 Wis2d 31, 315 NW2d 703 (1982) (upholding peremptory substitution statute). It remains unclear how alleging good faith, and subsequently proving it at a hearing called at the instance of the challenged judge, may remove a constitutional taint from ORS 14.260(1). See Foster v. Zeiler, supra, 283 Or at 259-60 (Linde, J., concurring).
The legislature, however, has enacted a statute requiring good faith, providing for a hearing to challenge good faith, and placing upon the challenged judge the burden of proving bad faith. Defendant seizes on the latter to argue that the legislature thus has enacted a peremptory challenge statute of the kind struck down in State ex rel Bushman v. Vandenberg, supra, because, taken together with the now-permitted conclusory affidavit, there is, practically speaking, no way to prove bad faith or to show lack of substance in the affiant’s allegations. To defendant’s credit, there is language from a previous decision of this court, State ex rel Lovell v. Weiss, supra, that might support his argument. Requiring the challenged judge to prove bad faith, however, leaves intact the requirement for alleging good faith; it also leaves intact the means for challenging the allegation. Although the challenged judge may confront undesirable problems of proof, undesirable problems of proof are not unknown, see ORS 133.693 (motion to controvert) and State v. Hitt, 305 Or 458, 753 P2d 415 (1988), nor do these problems render ORS 14.260(1) the kind of statute condemned in State ex rel Bushman v. Vandenberg, supra.
We thus conclude that ORS 14.250 and 14.260(1) pass constitutional muster.
A final note: In their answering brief, relators raised for the first time a new “assignment of error.” By reference to a trial court order in an unrelated case, relators contend that a party can disqualify a judge “at any step of any proceeding.” See ORS 14.270. Neither the petitions for the writ nor the alternative writs issued by this court address the timing issue now raised by relators. We decline to consider the issue on this record.
Defendant’s motion to dismiss is denied. Defendant shall have 10 days from the date of this order to file Answers to *619the alternative writ in each case. Unless Answers are filed, peremptory writs shall issue consistent with the Alternative Writ in each case.
There has been a change in the person filling the office of the presiding judge since these proceedings were filed. This does not affect our resolution of the issues presented, however. See ORAP 12.10.
Defendant actually phrases the issue in this way: Whether the amended provisions “so unduly burden or interfere with the judicial functions * * * that it [sic] runs afoul of the Constitutional provisions relating to separation of powers. Its resolution now turns on whether or not there is in fact ‘undue interference.’ ”
By referring to “separation of powers,” defendant presumably invokes Article III, section 1, of the Oregon Constitution. When Article III, section 1, is invoked, we inquire into whether one governmental branch has exercised the functions of another branch. Circuit Court v. AFSCME, 295 Or 542, 547, 669 P2d 314 (1983).
In this case, however, the legislature did not exercise a judicial function by providing rules for disqualification. Rather, it plainly exercised its own function — legislation. Strictly speaking, a “separation of powers” problem is not presented.
In State ex rel Ray Wells, Inc. v. Hargreaves (TC No 16-87-00357), this affidavit *616was filed:
“I, [name of attorney], being sworn say:
“That I am the attorney for the Plaintiff in the above entitled lawsuit. That [name of judge], is prejudice [sic] against my interest, so that I believe that my clients cannot receive a fair and impartial hearing or trial before this Judge.
“This affidavit and accompanying motion are made in good faith and not for purposes of delay. This is the first such motion filed in this case by Plaintiff.”
In Wells, relator’s attorney subsequently filed an additional, more detailed affidavit, apparently to comply with the requirements set forth in State ex rel Oliver v. Crookham, 302 Or 533, 731 P2d 1018 (1987). The affidavits filed in State ex rel Earle v. Hargreaves (TC No 16-86-05386) and State ex rel Fleming v. Hargreaves (TC No 15-84-05514) apparently comply with Oliver.
Section 45-2, Oregon Laws, as amended by chapter 143 of General Laws of Oregon for 1925, provided in part:
“Any party to or any attorney appearing in any action, suit or proceeding in a circuit court may establish [the prejudice disqualifying the judge] by motion supported by affidavit that the judge before whom the action or suit is pending is prejudiced against such party or attorney, so that such party or attorney cannot, or believes that he cannot, have a fair and impartial trial before such judge. And, that it is made in good faith and not for the purpose of delay.”