As long as there have been American elections, foreign powers have sought to influence them. George Washington and John Adams were targeted by French revolutionaries during 1796, and Nazi Germany tried to undermine President Franklin Delano Roosevelt's reelection campaigns.
Dov H. Levin, a professor of international relations at the University of Hong Kong and the author of Meddling in the Ballot Box: The Causes and Effects of Partisan Electoral Interventions, accepts as fact that powerful governments will intervene in other nations' elections for strategic purposes. America has certainly done plenty meddling of its own, mostly during the Cold War (significant interventions in Argentina and Guatemala get special attention here), with a mixed track record of success.
Yet intervening in foreign elections is less common than you might expect. The risks are high and the rewards often elusive. Trying to futz with an election is unnecessary if you can rely on the usual diplomatic channels to get what you want, Levin concludes.
Still, even marginal influence can have an effect. Without the media attention generated from leaked emails and other documents attributed to Russian interference, Levin believes Hillary Clinton would have won the 2016 popular vote by an extra 2 percent over Donald Trump—enough to win the key states of Michigan, Pennsylvania, and Wisconsin, along with a few others. Though Russia's meddling "has frequently been described in the public discourse utilizing various synonyms to the word 'unprecedented,'" Levin writes, "that is far from being the case."
The 2020 election had plenty of weird twists and controversial turns, but thankfully the controversies seem to be largely domestic. There's something unsettling about foreign election meddling—which can be particularly destabilizing if it reduces public trust in the ability of election officials to run clean contests, even if it is also inevitable.