USCA11 Case: 21-12355 21-12355 Date Filed: 05/23/2022 Opinion of the Court Page: 17 of 67 17 (2) irreparable injury will be suffered unless the injunction issues; (3) the threatened injury to the movant outweighs whatever damage the proposed injunction may cause the opposing party; and (4) if issued, the injunction would not be adverse to the public interest.” Siegel v. LePore, 234 F.3d 1163, 1176 (11th Cir. 2000) (en banc). Likelihood of success on the merits “is generally the most important” factor. Gonzalez, 978 F.3d at 1271 n.12 (quotation marks omitted). * * * We will train our attention on the question whether NetChoice has shown a substantial likelihood of success on the merits of its First Amendment challenge to Fla. Stat. §§ 106.072 and 501.2041. Because we conclude that the Act’s content-moderation restrictions are substantially likely to violate the First Amendment, and because that conclusion fully disposes of the appeal, we needn’t reach the merits of the plaintiffs’ preemption challenge. 4 4 The only provisions that NetChoice challenges as preempted are, for reasons we’ll explain, also substantially likely to violate the First Amendment. Of course, federal courts should generally “avoid reaching constitutional questions if there are other grounds upon which a case can be decided,” but that rule applies only when “a dispositive nonconstitutional ground is available.” Otto v. City of Boca Raton, 981 F.3d 854, 871 (11th Cir. 2020) (quotation marks and emphasis omitted). Here, whether or not the preemption ground is “dispositive,” but cf. id., it isn’t “nonconstitutional” because federal preemption is rooted in the Supremacy Clause of Article VI. See La. Pub. Serv. Comm’n v. FCC, 476 U.S. 355, 368 (1986).