President Trump, for all his bluster and outward aggression, is a weak man. He eventually backs down when circumstances are right. For example:

He hasn’t fired Attorney General Jeff Sessions.

He hasn’t fired special counsel Robert Mueller.

He signed the Russia sanctions bill.

He fired Michael Flynn (and seems to have regretted it ever since).

He reaffirmed our support for NATO.

He signed a budget resolution without funding for the wall.

He did not withdraw from the North American Free Trade Agreement.

He now has singled out for condemnation the Ku Klux Klan, neo-Nazis and white nationalists.

We do not know if a certain combination of advisers prevailed upon him to do what he had so strenuously rejected. What is clear is that his position with his base is weakening and his overall polling numbers are still sinking. He hit a new low in Gallup at 34 percent approval and new high in disapproval of 61 percent. He, therefore, may be amenable to even more pressure going forward. So what “works” with him?

First, he would rather bully aides into leaving (e.g., Sessions) than take the initiative to remove them himself. If the victim of his bullying ignores him and keeps plugging away, Trump very well may back down.

Second, when it’s hopeless to resist (e.g., a veto on Russia would have been overridden), he’ll relent.

Third, when many Republicans are on the other side, he usually does not have the wherewithal to persist in a ridiculous position. In the case of Charlottesville, even allies such as Sen. Tom Cotton, R-Ark., singled out and denounced the white supremacist groups. When they are divided or egging him on (e.g., trade restrictionism; a commission to investigate non-existent, massive voter fraud; leaving the Paris climate agreement), he is much more likely to pursue his wrongheaded, even ridiculous position.

Fourth, when he doesn’t have to explain, answer questions or concede that he backed down, he is more likely to go along with the party. He had no signing statement for the Russia sanctions; he took no questions on Charlottesville on Monday. Remember, protecting his ego is his constant task, and hearing that he “lost” is unbearable.

And this goes back to two critical points about Republicans and the Trump presidency.

• First, he got to the presidency and continues to govern in extreme, abnormal ways because the Republican Party as a whole will not challenge him. If House and Senate leadership can drain the Trump swamp by requiring full disclosure of his tax returns, ending nepotism and enforcing the emoluments clause, they can speak with one voice to demand that alt-right heroes such as Stephen Bannon and Sebastian Gorka leave the White House. They can, once again, refuse to fund the wall – or the phony election fraud commission. Trump, we’ve learned, can be forced to back down when the deck is stacked against him.

Second, Trump has no real beliefs. Other than feeding his base, undermining his opponents, concealing his finances and racking up “wins,” he doesn’t much care what comes out of Congress. It’s therefore incumbent on constructive lawmakers, including the problem-solver caucus in the House, to set forth bipartisan, reasonable proposals on tax reform (not huge tax cuts for the rich), infrastructure, legal immigration (not slashing it in half) and shoring up the individual health care market. Trump lacks moral and political leadership; it’s time for responsible public figures to fill it.

As for Trump, Republican lawmakers, when appropriate, should denounce his lies, egregious pronouncements and wrongheaded polices. Otherwise, frankly, they should ignore him and instead follow an agenda that will draw bipartisan support. Most important, when Mueller comes out with his findings, they must, if warranted, impeach and remove the president. What we now know is if they are prepared to do so, he’ll quit first.