Russia’s attack on American democracy is now “incontrovertible.” That’s the view of National Security Adviser H.R. McMaster, who added last week that the Kremlin conducted a campaign of “disinformation, subversion and espionage” designed to disrupt the 2016 U.S. election.

McMaster, addressing attendees at last weekend’s Munich Security Conference, spoke just a day after 13 Russian individuals and three Russian entities were indicted on charges of interfering in America’s political process with “the strategic goal to sow discord in the U.S. political system.”

The indictments and the clear evidence should unite Americans in solidarity against a foreign adversary that clearly has malevolent intent toward America and other Western democracies. Encouragingly, many Americans have in fact set aside their political disagreements to recognize the gravity of the attack and Moscow’s relentless efforts to destabilize the West.

Except the man who matters most: President Donald Trump.

The president previously called allegations against Russia a hoax and has refused to implement economic sanctions specifically designed to respond to Russian interference, despite an overwhelming bipartisan majority in Congress voting to impose the penalties. He has parroted Russian President Vladimir Putin’s denials despite the former KGB agent’s long legacy of subterfuge. Conversely, Trump has denigrated U.S. intelligence and law enforcement agencies in a cynical fashion by consistently criticizing those who have dedicated their lives to keep Americans safe.

Indeed, he has tweeted digs about the dogged investigators who are working to hold the Russians accountable — conflating an FBI field office’s failure to thwart the Parkland, Fla., shooting with “spending too much time trying to prove Russian collusion with the Trump campaign.”

Congress should show its independence by boldly condemning the Kremlin, pushing anew for sanctions, and publicly supporting the FBI and intelligence agencies instead of echoing paranoia about a deep state in need of a purge. Congress must also continue to press Facebook and other social media sites to step up their efforts to counter Russian trolls.

Generations of Republicans were stalwart in defense of the West from the threats emanating from Moscow, which helped end the Cold War and usher in freedom to millions. Today’s Republicans should live up to that legacy by following the lead of U.S. Sen. John McCain, R-Ariz., and others who have reassured allies by denouncing Russian interference and defending NATO. Congress also can show its resolve by passing legislation proposed by U.S. Sen. Amy Klobuchar, D-Minn., to protect elections and increase online campaign ad transparency.

With Trump failing to uphold his duty to defend the nation, there’s little to stop Putin from orchestrating attacks on the 2018 and 2020 elections. That, all Americans should agree, would be incontrovertibly damaging.