The Mueller indictment of 13 Russian nationals for interfering with the 2016 U.S.

presidential election offers a remarkably detailed account of a complex plot to sow discord and influence the presidential contest in favor of Donald Trump. The indictment critically points to something else, though: It provides a roadmap for the Russians to do it all again, without violating any current campaign finance laws the next time.

Paragraph 50 of the complaint demonstrates the kinds of social media ads Russian government agents paid for during the last election season. Here are two relevant examples: “Hillary is a Satan, and her crimes and lies had proved how evil she is,” and “Vote Republican, Vote Trump, and Support the Second Amendment!”

If the Russians interfere in the next presidential election, expect to see more of “the Democrat is Satan” sponsored Tweets and fewer “Vote Trump” messages. Under current campaign finance law, as the Supreme Court and lower courts currently construe it, it may have been perfectly legal for the Russians to run those Satan ads without disclosing their identity.

As I explained in Politico back in September, while the federal courts have upheld laws banning foreign nationals from spending money to try to influence our elections, the laws have been interpreted to bar only “express advocacy”—ads that might say “Vote Trump” or otherwise expressly advocate for the support or defeat of a particular candidate—and not ads which avoid those magic words. The exception to this, thanks to the McCain-Feingold campaign finance law of 2002, is for certain ads (called “electioneering communications”) broadcast close to the election on TV or radio which feature a candidate’s name or likeness. So foreign nationals could not call Hillary Clinton “Satan!” in a radio ad broadcast close to the election (and Americans paying for such ads have to disclose their identity).

The rub, however, is that it was likely perfectly fine for the Russians to put such ads on the Internet and social media. As I explain in a forthcoming paper in the First Amendment Law Review, soon after the Supreme Court decided the 2010 Citizens United case, freeing corporate money in U.S. elections, a three-judge district court in a case called Bluman v. FEC upheld the federal law barring foreign spending in U.S. elections.

Crucially, however, the court read the spending ban to apply to express advocacy and not to “issue ads” like “Hillary is a Satan.” The court did so because a broader interpretation may have run into First Amendment problems that the conservative Supreme Court had flagged in the past. The Supreme Court summarily affirmed Bluman, meaning it agreed without issuing an opinion that the three-judge court decision was right (though not necessarily all of its reasoning). The upshot is that there is potentially a huge loophole for foreign and undisclosed issue ads on federal elections.

Indeed, Bluman means that some of the ads flagged in Mueller’s indictment in Paragraph 50 may not violate federal election law at all. And this may explain why Mueller did not bring any direct election-related charges, instead offering a broad conspiracy charge which included violation not only of federal campaign finance laws but also of the law requiring foreign agents to register with the government. Some of the conduct in the indictment may not be illegal at all.

What can be done for next time (and there no doubt will be a next time)? Proposed federal legislation known as the “Honest Ads Act” would extend the “electioneering communications” rules to digital ads, including those on social media. The bill, whose sponsors include Democratic Sen. Amy Klobuchar and Republican Sen. John McCain, appears to be going nowhere.

The Mueller indictment shows how the Russians learned how to interfere with our election, for example, by seeking out political advice from Americans that led them to target “purple states.” They will potentially learn this lesson too. Unless Congress passes a law like the Honest Ads Act, it will be quite easy for Russian trolls and other foreign actors to avoid the foreign money ban, as well as for Americans to run such ads and avoid disclosure.

Opponents of the bill, like the Institute for Free Speech, claim it will squelch too much free speech of Americans. The group, which is close to Senate Majority Leader Mitch McConnell (an ardent opponent of campaign finance laws) issued a statement after the indictment suggesting that the Honest Ads Act isn’t needed:

[The Russians] brazenly violated multiple campaign finance laws already on the books, including prohibitions on expenditures by foreign citizens, disclaimer rules, and mandatory reporting requirements. This supports the Institute’s position that proposals to respond to foreign interference with broad-based restrictions on American online issue speech, such as the ‘Honest Ads Act,’ miss the mark. Nothing in the Honest Ads Act’ would have made these violations more readily detectable.

The statement assumes that the Russians won’t learn the next time, and that if legislators made more of their abusive conduct explicitly illegal it would be pointless. But it’s not. If more of these ads were illegal, and American companies like Facebook had an obligation to police ads to make sure they are not coming from foreign sources, we would likely be less susceptible to this form of foreign attack in 2018 and 2020. When we do see these types of ads, we would be more likely to at least know who paid for them.

Passing the Honest Ads Act won’t be a panacea. For example, it would not stop some of the activity that Russians did which did not even mention a candidate, like urging black and Muslim Americans not to vote or trumping up false claims of voter fraud. But it’s a start.

The alternative of ceding American elections to the whims of hostile foreign powers is a lot worse.