concurring in part and dissenting in part.
I join the opinion of the Court, with the exception that I respectfully dissent from the Court’s holding that the District Court should have abstained and postponed resolution of ap-pellees’ constitutional challenge to § 23-1392, Ariz. Rev. Stat. Ann. (Supp. 1978), until this statutory provision had been construed by the Arizona courts.
It must be stressed that “[a]bstention from the exercise of federal jurisdiction is the exception, not the rule. ‘The doctrine of abstention ... is an extraordinary and narrow exception to the duty of a District Court to adjudicate a controversy properly before it. . . .’ County of Allegheny v. Frank Mashuda Co., 360 U. S. 185, 188-189 (1959).” Colorado River Water Conservation Dist. v. United States, 424 U. S. 800, 813 (1976). If a state statute is susceptible of a construction that would avoid or significantly alter a constitutional issue, however, abstention is appropriate to avoid needless friction “between federal pronouncements and state policies.” Reetz v. Bozanich, 397 U. S. 82, 87 (1970). But, as the Court today correctly points out, the state statute at issue must be “ ‘fairly subject to an interpretation which will render unnecessary or substantially modify the federal constitutional question,’ [Harman v. Forssenius, 380 U. S. 528,] 535 [1965].” Ante, at 306. (Emphasis supplied.) This is not the case with § 23-1392.1
Section 23-1392 provides in part:
“Any person who . . . violates any provision of this *315article is guilty of a . . . misdemeanor. The provisions of this section shall not apply to any activities carried on outside the state of Arizona.”
The District Court concluded concerning this provision that “[i]t would appear on [its] face . . . that it cuts across and covers the entire [Arizona Agricultural Employment Relations] Act, not just a limited area where a criminal penalty might be acceptable. It says in plain English that it applies to 'any person’ and further [that] any person 'who violates any provision of this article is guilty of a misdemeanor ....’” 449 F. Supp. 449, 453 (Ariz. 1978). The District Court found the provision unconstitutionally overbroad.2 Ibid.
The District Court is clearly correct that the language of § 23-1392 is ''plain and unambiguous.” 3 Davis v. Mann, 377 U. S. 678, 690 (1964). The statute is not “obviously susceptible of a limiting construction” that would avoid the federal constitutional question reached by the District Court. Zwickler v. Koota, 389 U. S. 241, 251 n. 14 (1967). Of course, as every attorney knows, any statutory provision can be made *316ambiguous through a sufficiently assiduous application of legal discrimination. The Court resorts to such lawyerly legerdemain when it concludes that abstention is appropriate because Arizona courts might perhaps find “that only limited portions of the [Agricultural Employment Relations] Act are susceptible of being Violated’ and thus narrowly define the reach of the penalty section.” Ante, at 307. But the potential ambiguity which the Court thus reads into § 23-1392 does not derive from the plain words of the statute. It is simply the Court’s own invention, not an uncertainty that is “fairly” in the statute.4
Abstention is particularly inappropriate with respect to § 23-1392 because the provision impacts so directly on precious First Amendment rights. The statute creates sanctions for violations of the provisions of the Agricultural Employment Relations Act that regulate the speech of employees and employers.5 This potential impairment of First Amendment *317interests strongly counsels against abstention. “The abstention doctrine is not an automatic rule applied whenever a federal court is faced with a doubtful issue of state law; it rather involves a discretionary exercise of a court’s equity powers. Ascertainment of whether there exist the ‘special circumstances/ Propper v. Clark, 337 U. S. 472, prerequisite to its application must be made on a case-by-case basis. Railroad Comm’n v. Pullman Co., 312 U. S. 496, 500; NAACP v. Bennett, 360 U. S. 471.” Baggett v. Bullitt, 377 U. S. 360, 375 (1964). Relevant to the exercise of this equitable discretion, are “the constitutional deprivation alleged and the probable consequences of abstaining.” Harman v. Forssenius, 380 U. S. 528, 537 (1965). “This Court often has remarked that the equitable practice of abstention is limited by considerations of ‘ “the delay and expense to which application of the abstention doctrine inevitably gives rise.” ’ Lake Carriers’ Assn. v. MacMullan, 406 U. S., at 509, quoting England v. Medical Examiners, 375 U. S. 411, 418 (1964).” Bellotti v. Baird, 428 U. S. 132, 150 (1976). Therefore, when “constitutionally protected rights of speech and association,” Baggett v. Bullitt, supra, at 378, are at stake, abstention becomes especially inappropriate. This is because “[i]n such [a] case to force the plaintiff who has commenced a federal action to suffer the delay of state court proceedings might itself effect the impermissible chilling of the very constitutional right he seeks to protect.” Zwickler v. Koota, supra, at 252.
Even assuming that appellees have the financial resources to pursue this case through the Arizona courts, appellees may *318well avoid speech that is perhaps constitutionally protected throughout the long course of that litigation, because such speech might fall within the cold shadow of criminal liability.6 The potential for this self-censorship is abhorrent to the First Amendment. It should be permitted by a court in equity only for the most important of reasons. It cannot be tolerated on the basis of the slender ambiguity which the Court has managed to create in this statute. Abstention on this issue is therefore manifestly unjustified.7
Because of the ambiguous relationship between § 23-1385 (C) and §23-1385 (B)(8), I concur in the Court’s holding that the District Court should have abstained with respect to § 23-1385 (B) (8).
The District Court also found § 23-1392 to be “unconstitutionally vague.” 449 F. Supp., at 453. The Court stated:
“Considering the enormous variety of activities covered by the Act, and the fact that . . . many of these involve First and Fourteenth Amendment constitutional rights, it is clearly a statutory provision so vague that men of common intelligence can only guess at its meaning.
“There is no way for anyone to guess whether criminal provisions will apply to any particular conduct, in advance, and it is clear that the statute is unconstitutionally vague and does not adequately define prohibited conduct and is, therefore, in violation of the due process clause of the Fourteenth Amendment.” Ibid.
The fact that §23-1392 is, for purposes of the abstention doctrine, “plain and unambiguous,” does not necessarily mean that it cannot be unconstitutionally vague for purposes of the Due Process Clause of the Fourteenth Amendment. The section may plainly and unambiguously create criminal sanctions for violations of sections of the Act which, considered as criminal prohibitions, would be unconstitutionally vague.
Even if the statute were ambiguous in the manner suggested by the Court, abstention would still be inappropriate. It is extraordinarily unlikely that, in a statute as complex and far ranging as this Act, a single adjudication could definitively specify the exact reach of §23-1392. In such circumstances, we have held that a federal court should not abstain from exercising its jurisdiction. As we stated in Procunier v. Martinez, 416 U. S. 396, 401 n. 5 (1974):
“Where ... , as in this case, the statute or regulation is challenged as vague because individuals to whom it plainly applies simply cannot understand what is required of them and do not wish to forswear all activity arguably within the scope of the vague terms, abstention is not required. [Baggett v. Bullitt, 377 U. S. 360,] 378 [1964], In such a case no single adjudication by a state court could eliminate the constitutional difficulty. Rather it would require 'extensive adjudications, under the impact of a variety of factual situations/ to bring the challenged statute or regulation ‘within the bounds of permissible constitutional certainty.’ Ibid.”
Section 1385 (B)(8), for example, makes it an unfair labor practice “[t]o induce or encourage the ultimate consumer of any agricultural product to refrain from purchasing, consuming or using such agricultural product by the use of dishonest, untruthful and deceptive publicity. Per*317missible inducement or encouragement within the meaning of this section means truthful, honest and nondeceptive publicity which identifies the agricultural product produced 'by an agricultural employer with whom the labor organization has a primary dispute. Permissible inducement or encouragement does not include publicity directed against any trademark, trade name or generic name which may include agricultural products of another producer or user of such trademark, trade name or generic name.” Section 23-1392 makes violation of § 23-1385 (B) (8) a crime.
Appellees may be deterred from constitutionally protected speech even if the regulations which the Agricultural Employment Relations Act otherwise imposes on their speech are permissible under the First Amendment. This is because criminal sanctions discourage speech much more powerfully than do administrative regulations. Such sanctions would thus be more apt to cause employers and employees to “steer far wider of the unlawful zone,” Speiser v. Randall, 357 U. S. 513, 526 (1958), and more likely to contract the “breathing space” necessary for the survival of “First Amendment freedoms.” NAACP v. Button, 371 U. S. 415, 433 (1963). For this reason, it does not follow that because the First Amendment permits certain speech to be regulated, it must also permit such speech to be punished. See Gertz v. Robert Welch, Inc., 418 U. S. 323, 348-350 (1974).
Because of the First Amendment interests involved, my view is that the District Court on remand should issue an injunction “to protect appellees against enforcement of the state statute pending a definitive resolution of issues of state law by the Arizona courts. See Harrison v. NAACP, 360 U. S. 167, 178-179 (1959).” Ante, at 312 n. 18.