Donald Trump is coming to the end of one of the most dramatic and unpredictable US presidential campaigns in living memory, scouring swing states for the undecided voters who might make a difference and who might be persuaded by his inflammatory message and swingeing assaults on his Democratic rival.

But as he campaigned in Ohio, New Hampshire and Pennsylvania on Friday, a new side of the Republican candidate emerged. He was doing something no-one expected: he was being predictable.

As Tuesday’s vote nears, Trump’s rallies are still raucous and he still fills them with wild accusations against Hillary Clinton. A recent favourite is that “if she ever gets into the Oval Office, Hillary and her corrupt friends would rob this country blind”. But his words have become more scripted and controlled, resembling less a Jimi Hendrix guitar solo, full of improvisation, more a jazz musician riffing off a standard tune from the songbook.

The enthusiasm of Trump’s crowds has not diminished – thousands swarm at every stop. On Friday they came to Atkinson, New Hampshire, Wilmington, Ohio, and Hershey, the home of the chocolate giant, in Pennsylvania. When the candidate asked “who is going to pay for the wall”, they shouted “Mexico” deliriously. Dressed in Trump merchandise, they were ready at the slightest provocation to chant “Lock her up” or “CNN sucks”.

But Trump seemed to sense something had changed. When trotting out his newest line, “Drain the swamp”, both a jibe at what he describes as a corrupt establishment in Washington and a description of his willingness to clean it up, the candidate seemed almost unenthusiastic. He has taken to apologising when the line comes up in speeches.

“I hated the expression,” he said on Friday. “It’s so hokey.”

Trump often notes how Frank Sinatra hated singing My Way, before he realised how much his audience loved it. For Trump the “swamp” slogan, which could come from almost any insurgent political campaign, mounted by either party, is the same thing. If his crowds chant it, he will go along.

Yet he is by no means hostage to his crowds. On Friday he guided them along, ensuring they booed the correct villain at the right time, be it Clinton, the media or nondescript globalists intent on taking away US jobs and prosperity.

Members of the press corps have become his unwitting accessories. They are penned in, surrounded, while Trump falsely insists that TV cameras are not showing the size of his rallies. That claim goads the crowd into booing the press, who he insists are “the most dishonest people”. At times, he will even call out reporters by name.

This has not provoked any incidents of physical violence – yet. The sensation is more like that of being an animal on display at the zoo. Trump supporters stand on the other side of the fence, gaping, making faces and occasionally shouting abuse.

Things tend to intensify as the hour gets later and Trump, who has rarely been punctual in recent months, falls further behind schedule. By then the crowds, subjected to a loop of the same five songs for several hours, are ready to let loose.

But for all the passion and rage that Trump stokes, there is a lack of the bizarre creativity that defined his early campaigning. The candidate who compared the acclaimed neurosurgeon Ben Carson to a child molester and falsely said Texas senator Ted Cruz’s father was involved in the assassination of John F Kennedy has been left claiming, wrongly, that Clinton is the subject of multiple criminal investigations. While he has made “Crooked Hillary” a Homeric epithet to rival his labelling of former Florida governor Jeb Bush as “Low Energy” or his nicknaming Florida senator Marco Rubio “Little Marco” and Cruz “Lyin’ Ted”, it has not had the same effect.

The issue is perhaps the lack of any new villains to accompany Clinton, one of the most famous women in the world. Veering away from President Obama, Trump rails against nameless “global special interests” who he says ship jobs overseas and leave US borders open. But these attacks are not delivered with the gusto he uses for individuals. He is far more animated when calling for Clinton to fire her campaign chairman, John Podesta, because Podesta described his candidate as having “bad instincts” in a hacked email, than he is when reading a scripted attack on globalists.

The overall effect is of an ageing rock star, living off the glory of past hits. Trump still takes time to recall 16 June 2015, when he came down “that famous escalator” at Trump Tower in New York City to announce his campaign. He will often relive moments of glory in his bid for the Republican nomination. Ardent fans show up and buy the merchandise and the star is able to put on a show. But it is an increasingly mechanical exercise.

Trump has always been an awkward fit, somewhere between entertainer and politician. After all, the best shows and the most applause-worthy lines don’t always poll the best. At least for the next few days, though, he is willing to repeat his intent to “drain the swamp”, in order to maintain his shot at winning the White House.