In a day of testifying on Capitol Hill, former special counsel Robert Mueller spent much of his time declining to address matters raised by House members. But he was strikingly forthright on one issue. "Over the course of my career, I've seen a number of challenges to our democracy," he said. "The Russian government's effort to interfere in our election is among the most serious."

His report noted that the Kremlin meddled in the 2016 election in "sweeping and systematic fashion." Asked by Rep. Will Hurd, R-Texas,if the Russians might try again, Mueller replied, "They're doing it as we sit here, and they expect to do it during the next campaign." Mueller also warned that other countries could follow suit.

On Thursday, he got backup from the Senate Intelligence Committee when it released a bipartisan report outlining just how broad and alarming those past efforts were. "The Russian government directed extensive activity, beginning in at least 2014 and carrying into at least 2017, against U.S. election infrastructure at the state and local level," the committee concluded.

It cited the testimony of Michael Daniel, President Barack Obama's cybersecurity coordinator, that all 50 states were targeted. It also found that the election infrastructure was "sorely lacking" in safeguards and that even today, "some of these vulnerabilities remain."

Illinois got special attention in the report. The Russians broke into the state voter registration database, gaining access to as many as 200,000 voter registration records and obtaining names, addresses, birthdates, driver's license numbers and partial Social Security numbers.

The intruders, said the report, "were in a position to delete or change voter data, but the committee is not aware of any evidence that they did so." Not exactly comforting, is it?

There are ways to make election systems more secure. Among those the committee suggests are regular security audits, two-factor authentication for access to state databases and backup paper ballots. Among the steps to be avoided: online voting, because "no system of online voting has established itself as secure."

Director of National Intelligence Dan Coats recently appointed intelligence veteran Shelby Pierson to a newly created position to oversee election security to "bring the strongest level of support to this critical issue." Congress has also provided $380 million to help states replace old voting equipment and take other cybersecurity measures. Democrats say that's not enough, but The Washington Post reports that regardless, "it would be difficult to make substantial upgrades in time for the 2020 elections."

It's probably beyond the capability of the Russians or other governments to actually change the outcome of an election without being discovered. But Alex Stamos, director of the Stanford Internet Observatory, says they wouldn't have to.

It would be much easier, he told NPR, simply to "cause complete chaos on the day of the election and to create an information environment in which half the country believes that they didn't lose fair and square, that they lost because a foreign adversary hacked voting machines."

It's hard to overstate the need for vigilant action to protect the 2020 elections from foreign interference. The health of American democracy depends on it.

Chicago Tribune, Saturday