President Trump with Russian President Vladimir Putin in Helsinki on Monday. (Pablo Martinez Monsivais/AP)

As I touched down in Helsinki two days ago, I had one small hope — that the “summit” between President Trump and Russian President Vladimir Putin would not be a historic one. During my five years serving in the Obama administration, I attended many summits, meetings and talks with Presidents Dmitry Medvedev and Putin. Almost all were memorable to me, enough that I’ve written about them in my book, “From Cold War to Hot Peace: An American Ambassador in Putin’s Russia.”

But I would like to hope that I’m fairly realistic about these things. I know that most Americans, and probably most Russians, can barely remember any of them. Does anyone recall President Barack Obama’s summit with Medvedev in Moscow in July 2009, or the “pivotal” reciprocal summit in Washington the following June? Can anyone besides me recall what happened at the Obama-Putin meeting in Los Cabos, Mexico in the summer of 2012? I’m guessing “no.”

Before Monday’s meeting between Trump and Putin, I believed the best we could hope for in Helsinki was a non-event. We knew ahead of time there would be no deliverables: there was no agenda, as there usually would be, with specific items for the advancement of U.S. national interests. The two presidents began the day by meeting one-and-one for just more than two hours, and the substance of that encounter is likely to remain in the dark. That left only the news conference. For the sake of U.S. national interests, I was hoping neither president would say anything memorable or meaningful. A good Helsinki encounter would have been one that we could have soon forgotten.

Tragically, however, the Helsinki summit did turn out to be historic. It will be remembered as the most appalling public display of capitulation by a U.S. president to a Kremlin leader ever.

Expectations for this summit were so low, all Trump had to do was push back ever so slightly against Putin’s belligerent actions. That would have been enough for many observers to declare the meeting a Trump victory. All the U.S. president had to do was to utter the word “annexation” — a reference to the illegality of Russia’s takeover of the Ukrainian territory of Crimea. He could have deplored the brutality of Putin’s ally, Bashar al-Assad, in Syria. He could have warned that the Trump administration would not tolerate any foreign interference in our elections. It would have been so easy.

But Trump didn’t do anything of the sort. Instead, he lavished praise on Putin and avoided bringing up any uncomfortable topics. He then went a step further, siding with Putin against his own director of national intelligence, Daniel Coats, by restating that the Russian government did not intervene in the 2016 presidential elections. Trump even referred to Putin’s “strong and powerful denial.” Uttering those words, Trump looked weak, even intimidated.

I was shocked. Putin suspected that this meeting was going to go well, but for Trump to side with the Russian leader against his own government on a world stage must have been a stunning surprise to the Kremlin’s delegation. Russian Foreign Minister Sergei Lavrov looked downright giddy when he described the meeting as “better than super.” “Giddy,” by the way, isn’t the kind of word you’d normally use for Lavrov. But it captures the historic essence of Helsinki: It was a fantastic win for Putin, and an embarrassing performance for Trump.

And keep in mind — this was the public part of the Helsinki summit. Who knows what was said, what concessions were made, behind closed doors? Apparently, the U.S. government is now planning to debrief Trump’s interpreter during the one-on-one meeting to have at least some idea of what the two leaders said to each other, since no note-takers or other aides were present. Will our government manage to figure out in full what the two men discussed?

Trump failed on other counts as well. A few days earlier, he had erroneously described the European Union as a “foe”; standing next to Putin, he called Russia a “good competitor” — and added, in case anyone didn’t get it, that this was a compliment. Not once did Trump mention the destructive Russian actions — invading Ukraine, propping up the most brutal dictator in the world in Syria, or violating American sovereignty during our 2016 presidential election — that caused the deterioration of our relations with Russia. The only word that came to my mind was “appeasement.”

At this stage in the Trump presidency, the best we can hope for is that there will be no more Russian-American summits. A year and half into his presidency, Trump has demonstrated neither the desire, nor the capacity, to contain Putin’s Russia. The less Trump is involved in Russia policy, the better.

The Helsinki summit did have one positive result: Americans and the world were watching. For anyone who is in doubt before, Trump has now demonstrated just how far he’s willing to go to show his friendliness toward the country that attacked our democracy. For his part, Putin openly admitted that he wanted Trump to win the 2016 presidential election. Hopefully, the American public will now understand just how bizarre, unprecedented and even dangerous this relationship between Trump and Putin really is. We can only hope it will prompt American society to mobilize to limit future damage.

Read more:

Garry Kasparov: The Helsinki summit marks a new low in the history of the U.S. presidency

Fred Hiatt: Please, Dan Coats. For the good of the country, don’t resign.

The Post’s View: Trump just colluded with Russia. Openly.

Dana Milbank: We are a deeply stupid country

Max Boot: We just watched a U.S. president acting on behalf of a hostile power