“Trump’s policies without Trump.” Not a few Americans have expressed the attraction of this idea since Donald Trump threw his hat in the ring in 2015. It dawned on some immediately, others gradually, depending on how much tolerance one had for his mouth and demeanour.

The belittling nicknames Trump coined for his opponents during the 2016 campaign were singularly amusing, and his reference to the Washington establishment as “the swamp” resonated with tens of millions of voters. But he took insults to new lows, like when he questioned whether the late senator John McCain, who spent years in a Hanoi prison during the Vietnam war, was a war hero. Campaigns are nasty. Trump delivered.

Assuming at least some people who joined his administration advised him to put a lid on it when he became president, that advice was ignored. He never transitioned from the brawler of his campaign to being “presidential”. Whatever that word means, it is how Americans largely want and expect their president to behave. There are nice and diplomatic ways to say even unpleasant things; Trump couldn’t be bothered.

By the time he left the White House, many had concluded he was simply incapable of governing his behaviour, which disqualified him from governing the country. His actions, and lack of, on January 6, 2021, punctuated that. Good riddance.

But three years is a long time in politics. And a modestly new Trump seems to have emerged. “Modestly” and “seems” are key words here. He’s not exactly kinder or gentler – qualities associated with the tenure of his Republican predecessor George Bush senior – but he also doesn’t seem to be quite the same repellent Trump of his earlier campaigns and White House years.

His behaviour in last week’s debate suggests a new level of maturity, some lessons learned, some humility acquired, better manners. In short, he’s mostly keeping a lid on it. Given the small number of votes by which he lost critical states in 2020, a little behaviour modification is not a bad idea. There’s nothing weak about playing nice for votes.

It’s not easy to like Trump. But many Americans now know things they did not in 2016 and 2020, which may make him a little less unlikeable. They have seen the evidence from the John Durham investigation and trials that points to the Hillary Clinton campaign as the origin of the Russia collusion hoax in 2016.

They have seen the evidence from three House committee investigations about Hunter Biden’s laptop, including evidence that points to the Biden campaign as the origin of the effort to paint it as more Russian election meddling and effectively censor news about it just before the 2020 election.

So, while they might not like Trump, they really don’t like a lot of what they have now seen and heard about what his opponents have done to him.

“Drain the swamp” is a pithy slogan to Trump’s voters, but to him and his family, wading into it and taking on the Washington establishment is a real and personally perilous thing. He knows this yet shows both the courage and resolve to press ahead.

President Joe Biden’s performance during the debate might have shocked those who eschew conservative media, but his cognitive challenges have been apparent for quite a while, though not well reported by liberal media. The debate damaged his re-election chances; just how bad the damage is we may find out well before November arrives.

If Trump is really trying to be less of some of the things that made “Never Trumpers” a term, if he really has learned a lesson about his behaviour, voters may reward that on election day because his policies – on immigration, the economy and foreign affairs – appeal to many across the political spectrum.

If he can keep his mouth and manners largely in check, he might not just attract voters he turned off in 2016 or 2020, he might even convert some who voted for Bill Clinton or Joe Biden just because they didn’t like Trump.

And if he does that, he might not only win enough votes to take back the White House, he might win enough to put to rout the inevitable claim from Democrats that Russia somehow helped him do it. Because you just know that, or some new rendition of it, is coming if he wins.

But don’t bet the ranch on Trump maintaining his equanimity throughout the campaign. A lot can happen between now and November.