Going back to America’s early days, there have been occasional instances in which presidents would have been justified had they sought foreign investigations into political rivals. In 1804, Aaron Burr contacted the British government, apparently to peddle a plan for severing part of the United States to form a new country in western territory. In response, President Thomas Jefferson had Burr prosecuted for treason, and he was found not guilty. We can stipulate that Jefferson was excessively involved in the treason trial. But had he instead simply asked for Britain’s assistance in gathering more information about Burr’s involvement in this plot, that would have been entirely appropriate given the high stakes for the country.
This is true despite the fact that Jefferson was seeking reelection at the time and Burr, an incorrigibly ambitious politician, might still have coveted the presidency. It was unlikely that Burr would have been a serious rival to Jefferson’s reelection; the Federalist party, which opposed Jefferson, hated Burr for having slayed its hero, Alexander Hamilton. But Burr was still active politically and could not be discounted completely. Whatever the circumstances of the electoral rivalries at that moment—and campaigns back then were, of course, very different from today—Jefferson as president would have been acting responsibly if he had requested Britain’s assistance in the investigation of Burr.