It's illegal for foreign nationals to try to influence an election in the United States. US companies with foreign owners, however, face no such restrictions.

And in a post-Citizens United world, it's difficult to tell where the money is coming from.

Citizens United took a case to the Supreme Court in 2010, claiming that corporations had the same First Amendment right to free speech as people, and as such could give money to political campaigns. The court agreed.

Now, an investigation by The Intercept has uncovered evidence that foreigners are in fact giving to campaigns in this presidential election, and giving big.

Jon Schwarz was the Intercept's lead reporter on the investigation.

“'Foreign nationals,'” says Schwarz, ”is a term that covers individuals, corporations and governments.” None can legally put money into the US political process, directly.

“But there’s a loophole in US law about corporations,” explains Schwarz. “If a company is incorporated in the United States, then it counts as an American corporation, for US campaign finance law. And that means any corporation incorporated in the United States, no matter its ownership — even if it is 100 percent owned by foreign citizens, or even a foreign government.”

While this may appear improper, it might be totally legal. “That’s a question that nobody can answer for sure,” Schwarz says.

The Federal Election Commission is supposed to investigate these gray areas, make rulings and punish violations. But as Schwarz’s reporting makes clear, the commission has been paralyzed for some time.

“I think — to normal Americans — this looks horrible and is completely inexcusable,” says Schwarz. “The way foreign influence generally works is not that it’s really one country against another. It’s more that the elites in two countries kind of collaborate to screw the regular people in both countries.”