Sen. Bob Corker’s warning that President Donald Trump’s recklessness could set the country “on the path to World War III,” issued in a New York Times interview on Sunday, is notable for a few reasons.

For one, this is a critique that many Democrats and even some Republicans have made for some time — and that even more Republicans are said to make regularly in private.

For another, this is coming publicly from a Republican senator in a conservative state who chairs a major committee, has worked closely with the administration, and has had strong relationships with several of its officials. So when he says he knows “for a fact” that there’s no “good cop, bad cop” act underway, we should take him seriously.

But perhaps most noteworthy of all is that Corker only felt empowered to make such a bold critique after he had decided to retire rather than run for reelection in 2018 (as he announced at the end of last month). Only Corker’s liberation from the concerns of electoral politics, it seems, has motivated him to say what he truly thinks.

His GOP colleagues in the Senate, though, are not so liberated. So though Corker has also asserted that “the vast majority” of his fellow Republican senators understand “what we’re dealing with here” — that they share his concerns about Trump’s temperament — most of them remain hesitant to publicly discuss the issue in public.

Because of that reticence, the discussion about what potentially to do about a president who according to some is dangerously unstable has been choked off. So the seriousness of the dangers Corker is warning about — World War III! — doesn’t seem matched by a similarly serious proposed remedy.

Corker’s plan A, it seems, is to hope that Trump will continue to rely on aides and administration officials who Corker thinks will keep his worst impulses in check.

There doesn’t seem to be a plan B.

Corker is bolstering a critique that has been made of Trump for some time

Though Corker’s comments to the Times’ Jonathan Martin and Mark Landler were in one sense stunning, in other ways they’re not surprising at all. Trump’s erratic behavior, temperament, and apparent instability have been the subject of much discussion during the campaign and throughout the beginning of his presidency.

Indeed, for well over a year, Democrats and Trump-critical Republicans have been making the case that there are reasons to be very worried about giving this person the nuclear codes — and that disaster, for the United States and the world, could very well ensue. Hillary Clinton said during her Democratic convention speech last summer that “a man you can bait with a tweet is not a man we can trust with nuclear weapons.” And conservative columnists like Stephen Hayes, Ross Douthat, and George Will have all expressed concerns about Trump’s basic stability and competence.

But there’s been a dueling line of thinking, particularly on the right, that these concerns are generally exaggerated by liberals and Trump haters. Some think Trump is more strategic and rational than he’s generally given credit for. Others purport to believe that his persona as expressed on Twitter just isn’t all that important, and claim that the administration itself appears to be in good hands.

Corker is saying he believes that’s not at all the case. And there’s reason to believe he knows of what he speaks. As the top Republican on the Senate Foreign Relations Committee, he has close relationships with many top administration officials. He’s clearly drawing on what they’ve told him by saying that there is no “good cop, bad cop” act, and that he knows “for a fact” that “every single day” administration aides are desperately “trying to contain him.”

Yet very few elected Republicans are willing to make this critique in public

And yet it’s hard not to notice in Corker’s comments how what should be a forthright discussion over Trump’s fitness for office has been so bizarrely warped by politics.

That is: Though many Republicans who aren’t currently in elected office have publicly asked tough questions about Trump’s basic stability and competence, very few in the GOP who actually hold elected office have decided to do so.

Corker’s own evolution is a case in point.

During the presidential campaign, Corker campaigned with Trump and spoke positively of him. And even through much of this year — as he considered whether to run for reelection in 2018 — he tended to avoid criticizing the president too much.

Only in the wake of controversy over Trump’s response to a violent white supremacist rally in Charlottesville, Virginia, in August did Corker begin to take a harsher line. “The President has not yet been able to demonstrate the stability nor some of the competence that he needs to demonstrate in order to be successful,” the senator said after that.

Finally, in late September — facing a possible primary challenge from the right — Corker announced that he would retire. And since then, he’s been more vocal in his criticism of Trump. He said this month that he believed Secretary of State Rex Tillerson, Secretary of Defense James Mattis, and Chief of Staff John Kelly were three officials “that help separate our country from chaos,” in contrast to unnamed others in the Trump administration. And now there’s this new exchange.

The sympathetic interpretation of his behavior is that up until now Corker has been playing an inside game, trying to use his influence to steer the administration in a more productive direction, and that he has only now concluded that this inside game has failed and he has to go public with his concerns.

The more critical interpretation is that up to this point, Corker willingly ignored danger signs about Trump that were evident to basically everyone during the campaign, pulling his punches in part because he was afraid of angering Republican voters in case he decided to run again.

Partisanship and careerism have trumped concern for country

Indeed, perhaps the most striking comment Corker made to the Times is that “the vast majority” of his fellow Republican senators understand “what we’re dealing with here” — because you sure wouldn’t know it from their public comments.

It’s long been clear that the more concerned with reelection Republicans are, the less appetite they seem to have for criticizing Trump in any way. The reason is obvious — Trump remains quite popular among GOP voters, and any electoral official criticizing him risks drawing a pro-Trump primary challenger.

For instance, Sen. Jeff Flake (R-AZ), who wrote a book criticizing Trump this year, is performing dismally in primary polls. And with former White House chief strategist Steve Bannon preparing to back a slate of GOP primary challengers, it’s becoming more and more difficult to see Republicans critical of Trump having a future in GOP politics.

Additionally, Speaker Paul Ryan and Majority Leader Mitch McConnell, responsible for retaining Republican majorities in Congress, have attempted to avoid conflict with the president this year, and to work with him rather than criticize him.

It certainly is inconvenient for Republicans who genuinely want conservative judges appointed, tax cuts passed, and continued GOP electoral wins to put all that at risk by admitting that their president could be dangerously unstable.

But if they do in fact hold these concerns, a conversation needs to ensue about what they propose to do about it — and that conversation needs to happen in public.

Because as of right now, the best idea Bob Corker has — to essentially hope that Trump’s advisers continue to rein him in — isn’t particularly comforting.