Four years ago, for an embarrassingly modest price, Russia pulled off one of the more audacious acts of election interference in modern history. The Internet Research Agency, the team of Kremlin-backed online propagandists, spent $15 million to $20 million and wreaked havoc on the psyche of the American voter. Russian intelligence agents carried out the digital version of Watergate, infiltrating the Democratic Party and the Clinton campaign, stealing tens of thousands of emails, and weaponizing them in the days and weeks before the election. Russian-based hackers tested election websites in all 50 states for weak spots. The Russians were testing whether our windows were open, rattling our doors to see whether they were locked, and found the windows and doors wide open," says Sen. Mark Warner (D-Va.), the top Democrat on the Intelligence Committee. The Russians ... recently hacked the Ukrainian natural-gas company at the center of the Trump impeachment scandal to potentially find damaging material about the Biden family. Other foreign nations, including Iran, North Korea, Saudi Arabia, and China, are getting in on the act. They'll be joined, analysts say, by domestic actors - American consultants and candidates and click merchants borrowing and adapting Russia's tactics to influence an election or make a quick buck. "We're still in a situation going into 2020 where there are significant gaps left in the security of election infrastructure," says J. Alex Halderman ... who studies voting equipment.