FEC Chair Ellen Weintraub with this WaPo oped:

Concerns about foreign attempts to intervene in our political system date back to the founding of our republic. As chair of the Federal Election Commission, I am gravely concerned about ongoing efforts by geopolitical adversaries to undermine our democracy. It is critically important that everyone involved in U.S. politics understands the law, recognizes the threat, and confronts and contains it.

While the ban on foreign national spending in our elections is well established, unequivocal and clear on its face, a lot of people have raised good questions about the law’s scope.

It’s wide. Any amount of U.S. election spending by a foreign national is illegal. In 2012, the Supreme Court agreed with then-Judge Brett M. Kavanaugh’s conclusion that Canadian lawyer Benjamin Bluman’s proposed activity was illegal — not just his three proposed $100 campaign contributions but also merely paying to copy a flier supporting President Barack Obama’s reelection to hand out in Central Park. Bluman’s proposed activities were deemed illegal even though he hailed from a closely allied country, was lawfully working in the United States and had proposed spending only an inconsequential amount of money. That’s how broad the foreign national political spending ban is.