Tomorrow, the Supreme Court will consider a petition for a writ of certiorari in Hickenlooper v. Kerr. Colorado legislators challenged an enacted ballot initiative that prohibited legislative tax increases from taking effect without a popular vote, arguing that it violated the Guarantee Clause. A federal district court, and the Tenth Circuit, agreed that the legislators had standing and that the Guarantee Clause claim was justiciable.

I started tracking this matter over a year ago. I provide the background in these links; below that, I'll discuss the briefs in the case that the Court will consider.

• Tenth Circuit considers justiciability of Guarantee Clause today (Sept. 23, 2013)
• More thoughts on the Guarantee Clause from Michael Ramsey (Oct. 10, 2013)
• BREAKING: Tenth Circuit finds Guarantee Clause claim justiciable (Mar. 7, 2014)
• Kerr v. Hickenlooper: Exploring the Tenth Circuit's Dubious Legal Reasoning, JURIST (Mar. 31, 2014)
• Colorado files petition for rehearing en banc in Guarantee Clause case (Apr. 4, 2014)
• BREAKING: Over four dissents, 10th Circuit denies en banc hearing in Guarantee Clause case (July 22, 2014)

Several amici were filed in the case, available at SCOTUSBlog. Of note (and these are very brief summaries of the major arguments):

• The Colorado Union of Taxpayers Foundation, the Mountain States Legal Foundation, and 22 Colorado state legislators filed a brief in support of the petitioner. They focused primarily on the fact that respondents' injury was abstract, because legislators never enacted a tax increase for the people to vote upon--instead, they simply alleged a dilution of legislative power. That cannot comport with existing standing doctrine. Only if the Colorado legislature enacted a tax increase, then saw the people reject it, would standing exist.
• The National Federation of Independent Business, along with several policy institutes, filed a brief in support of the petitioner. They emphasized the breadth of the impact of a finding that such a case is justiciable, because the decision invites judicial invalidation of direct democracy in a number of states on matters ranging from marijuana legalization to charter schools. They also noted that in the partisan gerrymandering context (Vieth v. Jublier), the Supreme Court has essentially required an articulation of judicially-manageable standards before the case could proceed. Here, the district court insisted (in a rather bizarre fashion) on holding a trial to determine what the Guarantee Clause demands.
• The Center for Constitutional Jurisprudence (with John Eastman) filed a brief in support of the petitioner. It focused upon the inability of the Tenth Circuit to distinguish existing precedent finding the Guarantee Clause usually non-justiciable. Regardless, the case presents a good vehicle for clarifying the language in cases like New York v. United States (1992) suggesting that the Guarantee Clause may be justiciable, and articulating that the standards for justiciability are not met in this case.
• Texas joined by five other states filed a brief joined in support of the petitioner. They argue that the text of the Guarantee Clause protects not the state legislature, but the people, and the States. They also cite other provisions like line-item vetos and supermajority voting requirements that may be called into question if this case is found justiciable.
• The Cato Institute (with Ilya Shapiro) and several other policy institutes filed a brief in support of the petitioner. It asked the Court to avoid addressing the issue of whether the Guarantee Clause is per se non-justiciable and instead emphasized that Colorado's Taxpayer Bill of Rights met the standard of a "Republican Form of Government," drawing heavily from source material at the founding.

The Supreme Court will consider the case tomorrow--and we'll eagerly await their decision as to whether to hear this case.