A Homeland Security Department official says hackers have targeted the voter registration systems of more than 20 states in recent months. (Susan Walsh/AP)

RUSSIA DID not sit out 2018. Americans received a reminder of that reality on the eve of the midterm elections, when Facebook removed 115 accounts the company believes were linked to an influence operation. The good news is, while Russia did not sit out 2018, the entities defending the election against incursions from abroad didn’t, either. And compared with 2016, that is progress.

Before Facebook removed those 115 accounts this month after a law enforcement tip, it removed hundreds of others in late August. Twitter did the same thing, and last month it also released data on operations on its platform that showed the extent of Russian and Iranian operations. Companies and their partners in civil society and the government have made the simplest malign tactics, such as having a single user run thousands of automated accounts, harder to pull off. They also managed to disrupt some coordinated campaigns before they had the chance to spread too widely to stop. As a result, Russian-linked accounts, according to researchers, appear to have failed to reach 2016 levels of engagement.

Russia also had less success than in 2016, and launched fewer salvos, in hacking election infrastructure — at least as far as is known. The Democratic Congressional Campaign Committee rolled out an unprecedented cybersecurity program ahead of the midterms, and while some abnormal activity was detected, the committee did not experience anything close to the hack and leaks the Democratic National Committee experienced in 2016. This falls in line with Homeland Security Secretary Kirstjen Nielsen’s insistence that critical election infrastructure was not tampered with, thanks in part to her department’s increased protection efforts.

But those who would undermine democracy have evolved their tactics in an effort to stay ahead of platforms’ policing work. Networks of automated accounts pushing out divisive propaganda on both sides of the political spectrum still found a place on the most popular platforms. And Russia may well be saving its powder for a 2020 assault.

There is plenty more that could be done to defend against such an attempt, from upgrading voting systems to appointing a White House cyber-coordinator to fighting even harder against online disinformation. The United States cannot become complacent because the 2018 election was not overrun with Russian interference. But it also cannot allow reports of interference to sow unwarranted doubt in the legitimacy of the vote and discord in society. That, after all, is exactly what the Russians want.