Special counsel Robert Mueller might not have had enough interest in Michael Cohen to keep the case within his purview, but that doesn’t mean his prosecutors aren’t interested in his connections to Donald Trump. The Wall Street Journal reported overnight that they have subpoenaed America Media about their six-figure payment to a woman who allegedly had an affair with Trump. Are they turning the screws on Cohen, on Trump, or on the National Enquirer? Inquiring minds want to know:

Federal authorities have subpoenaed the publisher of the National Enquirer for records related to its $150,000 payment to a former Playboy model for the rights to her story alleging an affair with Donald Trump, according to people familiar with the matter.

The subpoena from Manhattan federal prosecutors requesting information from the publisher, American Media Inc., about its August 2016 payment to Karen McDougal is part of a broader criminal investigation of Mr. Trump’s former personal lawyer, Michael Cohen, they said.

Investigators are probing any potential efforts by Mr. Cohen to suppress damaging information about Mr. Trump during the presidential campaign, including whether he coordinated with American Media to pay Ms. McDougal and then not publish her account, other people familiar with the matter said.

Prosecutors are examining whether the payment violated campaign-finance or other laws, the people said.

Did Cohen arrange the America Media payment to McDougal, who thought she was selling the story to get it published? Or did David Pecker, a supporter of Trump, pay that on his own? So far, the tabloid is keeping its collective lips sealed:

When the first Wall Street Journal story broke, the tabloid denied that it pays people in order to quash damaging stories about Trump, and rather that it was for “editorial discretion to publish her life story.”

Trump has a long-standing relationship with David Pecker — the chairman and CEO of the National Enquirer’s parent company, American Media Inc.

In a statement, American Media Inc. did not address the subpoena directly, but said it “has, and will continue to, comply with any and all requests that do not jeopardize or violate its protected sources or materials pursuant to our first amendment rights.”

Well, that’s the funny thing about the First Amendment and the FEC. Thanks to a boatload of campaign-finance regulations, many of them ill-considered, you can’t just pay money to shut people up as a means to help out a favored political candidate without registering it as an in-kind donation, and potentially running afoul of donation limits enforced by the FEC.

Ironically or not, this First Amendment claim is undermined by the fact that they never ran the story. It wouldn’t have been a problem for the National Enquirer to pay McDougal and then actually run the story (unless Pecker was a big Hillary Clinton supporter who was doing so to boost her campaign, in which case the First Amendment defense might not stick either). This is the kind of conflict which drove the Citizens United challenge — determining where the First Amendment ends in political speech, and where it becomes in-kind contributions to a campaign. In that case, the Supreme Court settled on the side of the First Amendment.

That, however, involved actual speech, not payoffs to silence it. The arrangement McDougal looks like a payoff to keep McDougal’s story from burning Trump before the election, as does Cohen’s payoff to Stormy Daniels. And that is going to be no es bueno with the FEC — assuming they can prove intent. That’s why they issued the subpoena, and will likely start demanding internal communications related to the McDougal contract. The question will be whether the FEC will come after America Media during or after the Cohen prosecution, and then after the Trump campaign if those internal communications reveal any kind of coordination.

If they do, the Cohen probe will pose more risk to Trump than Mueller’s investigation, at least from what’s been produced from the latter so far. Inquiring minds in the Southern District of New York will not be as easily quenched as those of America Media’s customers.