Read: Making sense of McCain-Feingold and campaign-finance reform

On the losing end in those cases were Chief Justice William Rehnquist and Justices Anthony Kennedy, Antonin Scalia, and Clarence Thomas. The latter three wrote numerous dissenting opinions arguing against the constitutionality of these laws. Rather than deferring to legislatures, courts should be extra skeptical of such incumbency-protection plans, they said. And rather than applying a lax level of scrutiny to figure out whether the government’s interests were justified, these justices said a stricter scrutiny was warranted. Kennedy, in his McConnell dissent, argued that ingratiation and access were not a form of corruption, but rather an essential form of democracy.

Supreme Court deference to democratically enacted campaign-finance laws changed dramatically as the Court’s personnel shifted, especially with the retirement in 2006 of O’Connor and her replacement with Justice Samuel Alito. In the years since O’Connor’s departure, the Court has not upheld a contribution or spending limitation under consideration, except one related to foreign spending in elections, which it upheld without argument or briefing. In Citizens United, Kennedy resurrected his McConnell argument about ingratiation and access not being corruption, this time for the majority. In a 2014 case, McCutcheon v. FEC, Chief Justice John Roberts all but laid out the road map to finish the work begun in Citizens United and start using much stricter scrutiny to review, and strike down, campaign-contribution laws. The two newest justices, Neil Gorsuch and Brett Kavanaugh, have both expressed great skepticism about the constitutionality of any campaign-finance limits.

And so it is somewhat of a mystery why the Court has not taken more campaign-finance cases as vehicles to free up more big money in politics. The Court has turned down numerous challenges to the soft-money portion of McConnell, which still stands. It has repeatedly turned down an attempt to reverse a 2003 case, which held that corporations cannot contribute money directly to candidates. (Citizens United concerned only corporate spending independent of candidates.) And just this past term, the Court turned down a case from the Ninth Circuit upholding strict Montana contribution limits, and another from the Fifth Circuit, upholding low contribution limits in Austin, Texas. The latter case garnered a scathing dissenting opinion from Fifth Circuit Judge (and former Thomas clerk) James Ho, who said that if people don’t like too much money in politics, the solution was to shrink the size of government.

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Perhaps the justices did not take these cases because they did not see them as ideal for overturning more precedent. Perhaps the Court is gun-shy about taking on more controversial issues that it could choose to avoid, when cases about guns, abortion, and LGBTQ rights wait in the wings.