Matchboxes with images of Trump and Putin in a shop window in Helsinki, FinlandLeonhard Foeger / Reuters

As a candidate, Donald Trump promised to run the U.S. government in the same way he ran his businesses. At his Helsinki meeting with Russian president Vladimir Putin, President Donald Trump honored that commitment.

According to the Russian government, Trump pledged the United States to a series of agreements on matters ranging from nuclear forces to Syria. The U.S. government seems to have no idea what those agreements might be—or whether they exist at all. It’s unclear whether even Trump himself knows what he promised or did not promise. Trump’s post-meeting tweets reference “implementing” things “discussed”—which implies some kind of agreement, but does not actually use the word.

The last episode of Trump’s personal diplomacy provides a disquieting precedent. Trump emerged from his meeting with North Korean dictator Kim Jong Un convinced he had gained dramatic new concessions. He tweeted triumphantly on June 13: “Just landed - a long trip, but everybody can now feel much safer than the day I took office. There is no longer a Nuclear Threat from North Korea. Meeting with Kim Jong Un was an interesting and very positive experience. North Korea has great potential for the future!”

In fact, the North Koreans conceded nothing on the nuclear issue. Trump boastfully contrasted his Korean breakthrough with the Obama approach. “President Obama said that North Korea was our biggest and most dangerous problem. No longer - sleep well tonight!” A month later, Trump has reverted exactly to the Obama policy of strategic patience and de-facto acquiescence to Korean nuclearization.

The whole thing was a con from the start, and even now it remains unclear whether Trump was in on the con—or was its dupe.

Is history repeating itself? Trump is advertising his meeting with Putin as his next triumph. The only alternative to supporting Trump is nuclear war with Russia, the president insists, as do his henchpeople, on the government payroll and off. But what happened?

Nobody knows. This ignorance most probably explains Sarah Huckabee Sanders’s astonishing comment when asked whether Trump was open to sending U.S. persons, including former Ambassador Michael McFaul, to Russia to be interrogated by Russian authorities.

“The president’s gonna meet with his team, and we’ll let you know when we have an answer on that.” Then, after a follow-up: “There was some conversation about it, but there wasn’t a commitment made on behalf of the United States.”

That’s the sound of someone playing for time. She understands how explosive it would be to confirm the story—and she has not given up hope that it may not be true. Yet she dare not outright deny it either. Who knows what the president might have said—and whether the Russians have a recording of his words?

Typically—in fact, almost invariably—the national-security adviser joins the president’s meetings with foreign leaders, especially adversarial ones. You may remember the famous picture of President Nixon talking for the first time with Chairman Mao. In the wider-angle image, Henry Kissinger shows up just outside the close-up frame. Or think of President Reagan and Mikhail Gorbachev in Iceland, chatting informally on a red couch—and surrounded by note takers, cabinet secretaries, and senior aides.

It’s highly disturbing that Trump would exclude his own national-security adviser from his conversations with Putin. The exclusion bespeaks a lack of presidential confidence in his closest foreign-policy aide. For Bolton to acquiesce is equally disturbing: It suggests overeagerness to hold on to a high office whose functions he is not trusted to perform.

And of course, from a public point of view, the solo meeting looks even worse. Putin helped elect Trump by means of a massive, clandestine espionage effort intended to sway the outcome of the 2016 election. For Trump to meet with his benefactor in private, emerging with secret commitments, lends credence to the very darkest suspicions about the Trump-Putin relationship.

Maybe that’s why somebody shared with The New York Times on Wednesday this stunning revelation:

Two weeks before his inauguration, Donald J. Trump was shown highly classified intelligence indicating that President Vladimir V. Putin of Russia had personally ordered complex cyberattacks to sway the 2016 American election.

The evidence included texts and emails from Russian military officers and information gleaned from a top-secret source close to Mr. Putin, who had described to the C.I.A. how the Kremlin decided to execute its campaign of hacking and disinformation.

The reporters on that story—David Sanger and Matthew Rosenberg—are two of the most seasoned and reputable national-security journalists in the United States. They would not have taken the decision to reveal such sensitive sources-and-methods information lightly; perhaps not unless a responsible person assured them the revelation would no longer put lives at risk. And that, in turn, raises the possibility that the sources that produced the January 2017 certainty have already been compromised, closed, or worse.

In the weeks after Donald Trump was elected, bad things started happening to senior Russian officials. Two of Russia’s leading cybersecurity figures were arrested and charged with treason in December 2016. Over the following months, Russian officials worldwide abruptly began dying in suspicious numbers and suspicious ways. A 61-year-old former FSB general was found dead in his car in Moscow on December 26, 2016. On December 20, 2016, a senior Russian diplomat was found dead in his apartment with a pillow over his head, and a fatal gunshot wound beneath the pillow. A lawyer for Sergei Magnitsky—for whom the U.S. sanctions law is named—tumbled from his fourth-floor apartment and nearly died from his injuries. And so the tally runs.

Are these coincidences? Or something more sinister? Trump inadvertently disclosed at least one high-level U.S. secret to the Russian foreign minister in the Oval Office in 2017. How secure are other secrets in his trust?

Usually, at moments like these, Congress would be subpoenaing documents and quizzing witnesses. As is, the Republican majority sadly shrugs. “We’re frustrated, too! But what can we do?”

The place to start is by pressing National-Security Adviser John Bolton. If he has the president’s confidence, he should attend the president’s high-level meetings. If he has lost the president’s confidence, that is something the country needs to know—and raises the question of why he has not already resigned. If Bolton is aware of agreements with Russia, he can be questioned about them. If the agreements have been withheld even from him—again, Congress needs to know why.

Congress can also put itself on record as not being bound by executive agreements not submitted to the Senate for ratification, as Senator Tom Cotton and 46 other Republicans did with regard to the Iran deal in 2015.

Congress can delve into whether Russia holds undue influence over the president, by, for example, subpoenaing his tax returns. While Congress’s subpoena power is not as broad as that of the courts, it has a powerful argument in this instance. At a minimum, it’s a matter Congress can litigate, rather than submit to Trump’s claims.

And if this Congress, even now, cannot think of anything more to do about what increasingly looks like the worst security risk in U.S. history, maybe it’s time to hire some congressional leaders with more creative imaginations.

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