Though the finale is still months away, experts are already dubbing 2016 the most expensive election in history: by March, presidential candidates and affiliated groups had already blown through $1 billion dollars. 

But thanks to Supreme Court decisions like Citizens United which loosened restrictions on who can donate money to campaigns and how much, It may be increasingly difficult to tell how much of that money is coming in from overseas. Homeland security expert and host of the "Security Mom" podcast Juliette Kayyem says that should cause concern about how foreign interests may influence our elections. 

She pointed to the example of the Right to Rise SuperPAC, which supported Jeb Bush. The Intercept reported in August that American Pacific International Capital, Inc., a corporation based in California but owned by two Chinese nationals, donated a staggering $1.3 million to the PAC.

"As long as they had an existence, some sort of address, they could be totally based in some other country, they could give to campaigns," Kayyem said. "What you're seeing now is these corporations are giving to PACs, giving to SuperPACs, and there's no capacity to stop it."

That means that—to use the example above—had Jeb Bush won, knowing that part of his victory was due to the infusion of foreign money from China, he may have felt beholden to act in certain foreign policy or business disputes in China's favor.

Kayyem acknowledges that the influence of special interests is a problem with large domestic donations too, but historically, international influences were kept out of politics.

"We've always had a distinction—and maybe that's antiquted—between a domestic influence on domestic elections, and international," Kayyem said.

To hear more from Juliette Kayyem, tune in to Boston Public Radio above.