Recent examples include the Trump/Flynn outreach to Russia; Republicans working with Benjamin Netanyahu over the objections of President Obama; Nancy Pelosi traveling to Syria to meet with Assad over the objections of President Bush; the various freelance diplomacy activities of Jimmy Carter and Jesse Jackson; Ted Kennedy working with the Soviets at cross purposes to the Reagan Administration; and, of course, Jane Fonda’s famous trip to Hanoi. These and more examples suggest that we should apply the usual caution that we should not seek to impose vague, complex, or elastic laws against our political enemies if we do not want them used against our friends.

All of these activities are subject to legitimate political criticism. But the dangers of giving the executive branch the power to criminalize them ought to be obvious. That’s especially true because the existence of a criminal statute gives prosecutors an excuse to open intrusive and draining investigations without ever bringing charges that will ever be tested in court. Experience shows the latter to be a test that few prosecutors are willing to hazard: not one person has been convicted under the Logan Act in 219 years on the books (which means, among other things, that its constitutionality has never been meaningfully litigated). Only two indictments have ever even been brought, one of a Kentucky farmer under (ironically) the Jefferson Administration, the second at the behest of Daniel Webster in 1852 in a dispute over competing plans to build a railway in Mexico.