Julian Zelizer is a history and public affairs professor at Princeton University, editor of "The Presidency of Barack Obama: A First Historical Assessment" and co-host of the "Politics & Polls" podcast. Follow him on Twitter: @julianzelizer. The opinions expressed in this commentary are those of the author. View more opinion articles on CNN.

(CNN) For the second summer in a row, President Trump stood in front of the press and demonstrated that he doesn't actually know what makes America great. The sounds of shocked gasps were audible from sea to shining sea on Monday as the US President stood next to Russian President, Vladimir Putin, in Helsinki and rebuked the US intelligence community in a breathtaking few minutes of political history.

The President's remarks were so stunning that there were even voices on Fox News who had to admit how badly Trump had performed (though some, like Sean Hannity and Tucker Carlson, still found ways to praise him ).

It would have been one thing had the President remained silent in front of Putin about the massive evidence of Russian interference in the 2016 US presidential election, or if he had only briefly acknowledged the situation so that he could move on to other issues. But President Trump made a very different decision.

He deliberately decided to offer favorable words about Putin and Russia, while casting doubt on those in the United States who have been raising the alarms about the very real threat that now exists to our electoral process.

On Tuesday, the President gave a half-hearted apology in which he explained that he misspoke when he said, "I don't see any reason why it would be" Russia that interfered in the election. Still, this didn't explain away the rest of his comments or his repeated tweets on this subject.

The threat to our election system is a direct strike against one of the best ongoing gifts from the US Constitution. Though the original system was far from perfect, previous generations have fought hard to expand the right to vote and to strengthen the process, from the direct election of senators to the passage of the Voting Rights Act of 1965, to make sure that the greatest possible portion of our electorate would be able to enjoy his fundamental right. Our elections have been essential to distinguishing our country from autocracies, dictatorships, and monarchies where democratic power has been checked or stifled.

When seven intelligence groups -- the CIA, the Office of the Director of National Intelligence, the FBI, the National Security Agency, the Justice Department, the House Intelligence Committee and the Senate Intelligence Committee -- agree that Russia interfered in the election, government leaders have a very serious problem on their hands. This is not a talking point to be debated nor is it partisan rhetoric to be refuted. It is a political crisis that needs to be addressed immediately.

But from day one of his administration, culminating with yesterday's press conference, President Trump has refused to do what is necessary to protect the integrity of our elections. He has repeatedly praised Putin, despite warnings from his intelligence community of the threat that Russia poses.

Director of National Intelligence Dan Coats has, in fact, recently warned that the "warning lights are blinking red again" regarding Russian cyberattacks. Trump has done little to ensure that the same problem won't occur again. His strongest words have been reserved for praising the leader of the country that was responsible for the problem.

Still refraining from directly calling President Trump out for his actions, former President Obama came pretty close to doing so during a speech in South Africa to honor the 100th anniversary of Nelson Mandela's birth, when he said : "I am not being alarmist, I'm simply stating the facts. Look around -- strongman politics are ascendant, suddenly, whereby elections and some pretense of democracy are maintained, the form of it, where those in power seek to undermine every institution or norm that gives democracy meaning."

The refusal to take our cherished election system seriously comes almost one year after the horror in Charlottesville, when the President engaged in the same sort of failure to appropriately place blame during a press conference following the white supremacist rally that resulted in a brutal death.

Standing in Trump Tower in New York City, the President shocked the world when he refused to come down hard against the demonstrators and what they represented. As in Helsinki, the President didn't understand or didn't care why his refusal to take a strong stand was also essential to demonstrate a genuine commitment to American exceptionalism.

The marchers in Charlottesville represented values that were fundamentally antithetical to the best part of nation's character -- pluralism. The vitality of this country has been built on the fact that so many different cultures, ethnicities and races co-exist within our borders. We are a nation of immigrants, we are a nation made up of different races, we are a nation shaped by the many, not the few.

The term "melting pot" has been used to connote this essential part of our character. Though there have been important debates about the need to preserve multiple cultural identities within the whole, there has been growing support over the last century that our heterogeneity is a great virtue. This was why the white nationalist rage on the streets of Charlottesville was so disturbing to large parts of the country. Just nine years after the country elected its first African-American President, a historic milestone of progress, President Trump was unwilling to firmly condemn the voices in this country that rejected this idea.

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Today the pundits are debating whether the President's comments were " treasonous ." Regardless of how that debate is settled, what should become clear is that his actions were unpatriotic.

Making matters worse, the press conference was not some kind of anomaly. Trump's attacks on voting rights , his support of hardline anti-immigration policies, his hostility toward the alliances of democracies in Europe, all point to the same worldview that proved so disturbing yesterday.

Without free elections and a pluralistic society, there is no way that the United States can actually be great. And on both of these measures, President Trump has been standing on the wrong side of history.