The investigation into the Trump campaign’s ties to Russia is serious, and becoming more so. But it is not what is imperiling Donald Trump’s presidency. What’s imperiling Donald Trump’s presidency is, well, Donald Trump.

Washington Republicans never liked or trusted Trump, but they hoped to be won over by his administration, to be persuaded that he was more disciplined and strategic than he appeared to be during the campaign. Those hopes have been dashed by the lawless, reckless way he has responded to ongoing inquiries. Trump has scared his allies, enraged his bureaucracy, undermined his credibility, and publicly admitted to using the power of his office to obstruct ongoing investigations. In doing, he has reminded Republicans what they feared a Trump presidency would be like — unconstitutional, unfocused, scandal-plagued, and damaging to both America’s standing in the world and the GOP’s brand at home.

“Republicans may soon lose a generation of voters through a combination of the sheer incompetence of Trump and a party rank and file with no ability to control its leader,” warned conservative radio host Erick Erickson.

“[F]rom the perspective of the Republican leadership’s duty to their country, and indeed to the world that our imperium bestrides, leaving a man this witless and unmastered in an office with these powers and responsibilities is an act of gross negligence, which no objective on the near-term political horizon seems remotely significant enough to justify,” wrote Ross Douthat at the New York Times.

Trump’s relationship with congressional Republicans is best viewed as an uneasy bargain. They support him, despite their doubts, so long as he passes their agenda and controls his behavior enough not to endanger them or the country. Trump is failing on his end of the deal, and he is making it harder and harder for congressional Republicans to hold up their end of the deal. That’s where the sudden talk of impeachment comes from, and the rising comfort with special counsels and independent commissions.

On Tuesday, Sen. John McCain warned that President Trump’s mounting scandals were “reaching Watergate size and scale.” That same night, Carlos Curbelo, a Congress member from Florida, became the first congressional Republican to use the i-word. “Obstruction in the case of Nixon and in the case of Clinton in the late ’90s has been considered an impeachable offense,” he said. Rep. Justin Amash quickly backed him up. Asked whether James Comey’s memo would, if verified, be grounds for impeachment, Amash said it would.

If the allegations in Comey memo are true, are they grounds for impeachment?@justinamash: "Yes." — Cristina Marcos (@cimarcos) May 17, 2017

This is a moment in which the tectonic plates that underlie political opinion in Washington are shifting, a moment in which the unthinkable is being thought, announced, and perhaps even hastened. As recently as two weeks ago, Republicans thought it safer not to know the crimes Trump may have committed or the lines he may have crossed. Today, the GOP is facing the grim reality that Trump is not disciplined enough, and the bureaucracy he leads is not loyal enough, to keep his misdeeds hidden. Key Republicans are concluding that the truth will emerge, and so they may as well be the patriots who uncovered it, rather than the hacks who suppressed it.

A sign of the times: I spoke on Wednesday to a top staffer in a conservative Senate office. What did he think of Vice President Mike Pence these days? I asked. “You mean the next president of the United States?” he shot back.

He was joking, kind of. But no one was making jokes like that two weeks ago.

How Donald Trump endangered his own presidency

Investigations — and calls for investigations — have swirled around Trump since the start of his administration, but congressional Republicans found it reasonably easy to ignore them. What they couldn’t ignore was what Trump did in reaction to the investigations launched by then-FBI Director James Comey.

First, Trump asked Comey to stop investigating Flynn. “I hope you can see your way clear to letting this go, to letting Flynn go,” Trump said, according to Comey’s notes. He also asked Comey to announce, publicly, that Trump was not under investigation. Comey refused both requests, and took notes on both encounters. This is a problem Trump created out of whole cloth.

Then Trump fired Comey over the FBI’s investigation into the Trump campaign’s contacts with Russia. The timing of the firing was bizarre, and the way it was handled alienated both Comey and the FBI. This, too, was a problem Trump created for himself.

There was a quasi-reasonable explanation for Comey’s firing, and the White House tried to offer it: Deputy Attorney General Rod Rosenstein, they said, had reviewed Comey’s controversial handling of the Clinton email case and concluded his credibility was compromised. But Trump blew that to shreds, telling NBC’s Lester Holt “regardless of [the] recommendation, I was going to fire Comey.” He explained: “When I decided to just do it I said to myself, I said, ‘You know, this Russia thing with Trump and Russia is a made-up story, it’s an excuse by the Democrats for having lost an election that they should’ve won.’” No one made Trump do this.

In an Oval Office meeting with Russia’s foreign minister, Sergei Lavrov, and the Russian ambassador to the United States, Sergey Kislyak, Trump bragged, “I just fired the head of the FBI. He was crazy, a real nut job. I faced great pressure because of Russia. That’s taken off.” Notes from that meeting were subsequently leaked to the New York Times, and press secretary Sean Spicer confirmed the account.

So, first Trump asked Comey to collude with him in obstructing justice — thus giving Comey the ammunition to torch Trump if he were ever crossed. Then Trump publicly fired and humiliated Comey. Then he publicly admitted he did it to quash the Russia investigation, which in turn primed the public to believe Comey when he said Trump also asked him to end the Flynn investigation. Then he bragged about it to Russian officials, because … I don’t know. I honestly don’t know what would possess a human being in Trump’s position to do that. Some things cannot be explained.

The remarkable thing, looking back on the timeline, is that none of it was necessary. Trump could have simply treated Comey well and tried to win him over as an ally while offering bland statements of support for his work. It wouldn’t have taken a political genius to choose another path here.

The obvious counterargument to all this is that Trump may believe Comey’s investigation posed an existential danger to his presidency. He may have felt his hand forced. But if so, he failed to extinguish the threat — in fact, he made it worse.

Trump embarrassed Rosenstein, and days later, Rosenstein appointed former FBI Director — and close Comey friend — Robert Mueller as special counsel to continue the investigation Comey had begun. Rosenstein made the appointment after giving the White House a mere 30 minutes’ notice — a move many attribute to his fury over his treatment at Trump’s hands.

Trump made both Comey and the FBI into enemies — a mistake that has already resulted in a torrent of leaks and damaging stories, and will continue as Comey testifies before the Senate this week.

By contradicting his own White House and making clear that he fired Comey to obstruct the Russia investigation, Trump made the investigation more interesting to the media, destroyed any credibility his aides had on the subject, intensified pressure on Congress to carry out its oversight duties, and heightened the suspicion his own actions are under.

None of this was a necessary consequence of Comey’s investigation. This is Trump recklessly, impulsively endangering his own presidency.

But it’s not just Comey

Again and again, Trump has taken small problems and, in his fury, turned them into huge problems. A partial list:

Trump’s feud with the intelligence agencies began in earnest after the CIA concluded that Russia had interfered in the 2016 election to help Trump win. Rather than being angry at Russia, Trump turned his ire on the CIA. "These are the same people that said Saddam Hussein had weapons of mass destruction," he replied. Shortly thereafter, he decided to dispense with the daily intelligence briefing that his predecessors received. “I don't have to be told the same thing in the same words every single day for the next eight years,” he said.

As it became clear that Trump’s associates had been eavesdropped on in the course of their conversations with Russian officials under US surveillance, Trump reacted with fury, and accused the Obama administration of wiretapping Trump Towers. There was no evidence for Trump’s claims, and, unusually, the heads of the FBI and NSA refuted him during sworn congressional testimony. The episode exposed Trump as a rash liar and frustrated congressional Republicans who were caught between an impulse to defend their president and the fact that his claims were indefensible.

A New York Times report revealed that Flynn informed Trump and the transition team that he was under Justice Department investigation for his role as a paid lobbyist for the Turkish government. Trump named Flynn national security adviser anyway.

Trump, it seems, has stayed in communication with Flynn, telling him to “stay strong” as recently as April. It almost goes without saying that continuing to communicate with an adviser who is under investigation and who you had to fire for lying about contacts with the Russians is unwise.

And then there’s the story that dominated the news mere days ago, and that served as the backdrop for exhausted Republicans absorbing the new information about Comey’s dismissal: Trump disclosed classified Israeli intelligence in a conversation with Russia’s foreign minister.

In a bombshell report, the Washington Post revealed that Trump gave Russian Foreign Minister Sergei Lavrov classified intelligence that had been provided to us by a third country (now believed to be Israel). As best anyone can tell, Trump’s actions were motivated by insecurity rather than malice — the context appears to have been Trump bragging about the quality of the intelligence he receives.

But the details Trump gave Lavrov were sufficient to endanger “a critical source of intelligence on the Islamic State,” according to the Post. That means that whatever Trump said made it possible for the Russians to figure out where the intelligence was coming from, which in turn means it’s possible that Israel will lose a key source of information on ISIS because of Trump’s actions. If that happens — and even if it doesn’t — this will severely damage Israel’s incentive to share sensitive intelligence with the United States, which could in turn put American lives at risk.

It is hard to overstate how much this gaffe horrified the foreign policy community. “On a scale of 1 to 10 — and I’m just ball parking here — it’s about a billion,” Stanford professor Amy Zegart wrote in the Atlantic. Zack Beauchamp does a nice job explaining why:

It’s easy for us to think that the United States gets most of its intelligence from CIA spies, satellite photos, or NSA intercepts. The truth, though, is that the US relies heavily on exchanges with partners in foreign intelligence services — like Israel’s Mossad — especially when it comes to ISIS and other terrorist groups. The US depends vitally on its partners in the Middle East to get inside of those groups and figure out what they’re planning. “As a matter of geography and language and culture, they are closer to the problem,” says Paul Pillar, a 28-year CIA veteran who worked on counterterrorism and the Middle East. “So they’re better able to collect against groups than we are.” Given the magnitude of Trump’s breach, this will almost certainly lead the partner in question, Israel if the Times is right, to least temporarily suspend intelligence sharing with the United States. That’s especially likely since it was Russia that Trump leaked to: The Israelis are deeply concerned about intelligence getting to the Iranians, and given that Russia is working closely with Iran to prop up Bashar al-Assad in Syria, there’s a very real risk that anything that gets to Moscow could end up in Tehran.

The disclosure was damaging enough that someone else present during Trump’s conversation with Lavrov reported the breach to the intelligence agencies. It is believed, though not confirmed, that the leak revealing Trump’s comments subsequently came from one of those intelligence agencies, perhaps in an effort to embarrass Trump, or perhaps in an effort to make clear to him that he has to be careful going forward.

Trump (probably) didn’t do anything illegal in revealing this information to the Russians. The president can declassify what he wants, how he wants, when he wants. But that power is predicated on the idea that presidents won’t misuse it.

The fallout is enraging not just to our allies abroad, but to Trump’s allies at home, many of whom would like the commander in chief to be sufficiently competent and careful that he doesn’t jeopardize our intelligence sharing agreements while offhandedly bragging about himself to the Russians.

Trump is proving the president Republicans feared he would be

Congressional Republicans never liked Trump. I’ve told this story before, but back during the primaries, I published a piece — and recorded a video — calling Donald Trump’s rise a terrifying moment in American politics. The analysis was unsparing.

"Trump is the most dangerous major candidate for president in memory," I wrote. "He pairs terrible ideas with an alarming temperament; he's a racist, a sexist, and a demagogue, but he's also a narcissist, a bully, and a dilettante. He lies so constantly and so fluently that it's hard to know if he even realizes he's lying."

After the piece published, I got a call from a very conservative Republican member of Congress. He wanted to talk about the article, his office said. I figured he’d be angry. Instead, he congratulated me for speaking out.

That member of Congress subsequently endorsed Trump. He did it because he felt he had no choice. Trump was going to be the Republican nominee, and the Republican base loved him, and so this official, who thought Trump a disaster, decided to get on the train.

This same story was repeated across almost the entirety of the GOP’s congressional wing. Sometimes, it even played out in public. Rand Paul called Trump a “delusional narcissist.” Ted Cruz said he was “utterly amoral” and “a pathological liar.” Marco Rubio warned that Trump was a “con artist” who was too “erratic” to control nuclear weapons. Lamar Alexander said Trump was “driving the presidential campaign to a new low.” Hell, even Mike Pence told friends that Trump was “unacceptable.”

All these Republicans eventually backed Trump — they did it out of loyalty to party or self-interest or a desire to pass tax cuts or because they believed they could do more good helping Trump from the inside than criticizing him from the outside. But no one believes they changed their minds about his basic fitness for office. They wanted to change their minds, they hoped to change their minds, and early on, as Trump named conventional Republicans to key posts and endorsed big swaths of Speaker Paul Ryan’s agenda, they were pleasantly surprised. Perhaps Trump was more than they had thought.

But in recent weeks, Trump has shattered their hopes, and Republican commentary has become despairing. “People on the inside say he keeps getting worse,” said Joe Scarborough on MSNBC. “This is not, unfortunately, a learning curve. ... This is a man in decline."

In a searing New York Times column (built in part on this excellent Dave Roberts analysis of how Trump thinks and acts), David Brooks wrote, “The Russian leak story reveals one other thing, the dangerousness of a hollow man. Our institutions depend on people who have enough engraved character traits to fulfill their assigned duties. But there is perpetually less to Trump than it appears.”

And it was Ross Douthat, also at the New York Times, who called for Trump’s ouster. “I respectfully ask Mike Pence and Paul Ryan and Mitch McConnell to reconsider their support for a man who never should have had his party’s nomination, never should have been elevated to this office, never should have been endorsed and propped up and defended by people who understood his unfitness all along.”

Putting aside the question of whether Trump should be president, what congressional Republicans are realizing is that their protection may not be enough to keep him as president, and that changes the calculus significantly. Trump has so infuriated the intelligence agencies that leaks will reveal his misdeeds whether or not congressional Republicans launch a real investigation. Trump can’t be confidently defended in public, because he will contradict his own White House and his own surrogates, making it dangerous for top Republicans to yoke themselves to his explanations. (On the night the Comey memo broke, Fox News’s Bret Baier complained that he couldn’t get a single Republican to come on his show to argue the president’s case.)

You can think of Republicans and Trump as caught in a prisoner’s dilemma: Both would benefit from cooperating to suppress the flow of awful stories about Trump, but if Trump is temperamentally incapable of acting in a disciplined, restrained manner, then it might behoove congressional Republicans to get ahead of the revelations about his conduct rather than being caught behind them.

Then there is the hardest question, the one that gnaws at the souls of even Trump’s protectors. Is this a man who can really be trusted with nuclear weapons, with the surveillance state, with America’s response to a genuine crisis? We are watching Trump respond to pressure and he is failing terribly. We are watching Trump faced with easy ethical dilemmas and he is failing miserably. So far, the consequences — with the exception of sharing Israeli intelligence with Russian officials — have mostly been confined to Trump humiliating himself. But it is easy to see how these same tendencies lead to disaster if and when Trump misjudges his response to a true emergency.

All this has left Republicans increasingly uncertain as to whether protecting Trump is wise for their careers, or for their country. “Chatter has begun about what a President Mike Pence might look like,” reports Politico.

As Douthat says, many top Republicans have long believed Trump unfit for the presidency, but they hid that belief in order to defeat Hillary Clinton, pass their agenda, and smooth their relationship with the conservative base. The danger Trump faces is that’s a thin sort of support to base your presidency on, and if it cracks — and it may already be cracking — it means there is a long, long way to fall. If every elected Republican said what they really thought about Trump, and acted accordingly, Trump’s presidency would be doomed.

The best analogy here might be the 2007 financial crisis, when subprime bonds went from riskless to worthless overnight, and the correction upended the economy. With Trump, too, the possibility exists for a massive correction in which Republicans go from “he should be president” to “he shouldn’t be president” very quickly — a correction that would not be too hard to make given that’s what most of them already believe, and given that the much better-liked Mike Pence waits in the wings. Trump, in the way he is reacting to his various scandals and managing his presidency, is almost daring them to make that correction.

Republicans will not vote for impeachment tomorrow. They know Trump’s fall would be a calamity for their party, and they would like to avoid it if possible. Trump’s actions in recent weeks, however, have persuaded many Republicans that it would be a good thing to have an independent commission or counsel investigate Trump, because if the worst happens and information is revealed that forces Trump’s resignation or impeachment, well, perhaps that’s not such a bad thing after all — particularly if Republicans can get some of the credit rather than all of the blame.