Russian President Vladimir Putin came late to the Helsinki summit with President Trump last week and spoke first at the news conference afterward.

He handed Mr. Trump a soccer ball from the World Cup, but he clearly walked away with the trophy for the World Cup of politics, largely because Mr. Trump, in a bizarre and unprecedented performance, kept scoring his own goals on Mr. Putin’s behalf.

I have always supported dialogue and negotiations over conflict and isolation. I believe that good relations with the Russians, a nuclear power, are as Mr. Trump would say, “a good thing.” But Mr. Trump made it embarrassingly clear that he is more concerned about defending his own besmirched election campaign than he is about protecting American democracy.

The president apparently doesn’t understand that it isn’t all about him. Russian interference in our elections — which Mr. Trump’s own intelligence appointees warn is ongoing — isn’t just about the “collusion” that the president rushed to deny. It is about subverting our democracy.

Mr. Trump can howl at the moon denying collusion, but it is simply grotesque that he could not bring himself to warn Mr. Putin publicly that continued interference with our elections is unacceptable and would be met with an immediate response.

Mr. Trump is outraged at special counsel Robert Mueller’s investigation of possible collusion of his campaign with the Russians, but he seems unmoved by the clear evidence of the subversion of our elections. He didn’t give Mr. Putin a red light or even a yellow warning one about future interference. He essentially gave Mr. Putin a free pass. The reality is that a core of our democracy — free elections — is under assault.

Given the administration’s failures, foreign interference is likely to spread. The home-grown systematic efforts by rightwing politicians and activists to suppress the vote, to make it harder to register and harder to vote, to purge voters from the lists, to gerrymander election districts to distort the outcome and to open the gates to a flood of unaccountable, secret corporate and private money continue to get more sophisticated.

Already, experts suggest that Democrats will have to win the national vote in November by 6 percent to 8 percent in order to take the majority of the U.S. House of Representatives largely because of Republican partisan redistricting.

Mr. Trump is so focused on his own re-election campaign, so defensive about the legitimacy of his own victory, that he has utterly failed to protect our democracy from subversion from abroad or at home.

It will be up to the states to make the reforms that are long overdue: Automatic voter registration, longer early voting days, voting day holidays, an end to voter purges, nonpartisan redistricting, matching public funds for small donations, mandatory disclosure of all funding sources, returning the right to vote to felons who have served their time and more.

The states should be taking measures to protect voting systems from outside interference, including moving back to paper ballots to eliminate the threat of cyber intrusions.

The president should be applauded for meeting with Mr. Putin. Hopefully, reduced tensions and new impetus for reducing nuclear arsenals will follow. But his failure to defend our democracy both against Russian interference and against domestic subversion is a dangerous dereliction of duty.

Republicans in Congress won’t act because they seem to believe that their majorities may depend on suppressing the vote. So, it is up to the states, and to an aroused citizenry, to insist that our election be open, free and fair. The shocking display that Mr. Trump put on in Helsinki makes that all the more imperative.

The writer is founder and president of the national Rainbow PUSH Coalition.