A war on "foreign influence" as a concept is likely to be as successful as the war on drugs and the war on terror. Perhaps it makes sense to look at each type of foreign activity separately. Fraud, theft, bribery, and blackmail should be crimes, whether the perpetrators are American or not. Foreign propaganda is probably an unavoidable part of living in a society with free speech, and the best solution to bad speech is more speech.

It would also benefit Washington to look in the mirror. The U.S. government interferes heavily in the politics of different countries around the world. And that's not just a matter of hypocrisy. U.S. involvement gives the affected countries a direct stake in U.S. politics. After all, swaying the vote of a few members of Congress could help redirect huge amounts of American guns and money. It's especially true when so much of U.S. national security policy is already made through backroom dealing rather than public debate.

Having a more modest, more transparent, and more carefully targeted foreign policy wouldn't end all foreign influence. But it couldn't hurt to try.