The Republicans have had four official debates to date, and the Democrats two. What have we learned, in terms of body language and communications dos and don’ts, from all this adrenalized effort? What works and what doesn’t?

Perhaps the most consistently surprising debater is Mr. Trump.

He began by completely dominating the first debate, taking all the other candidates by surprise to greater or lesser degrees. Trump stole the limelight even when he wasn’t answering questions by making faces and verbal interjections that brought the camera back to him time and time again.

I was preparing to re-write the debate rulebook, since what he was doing seemed to be working. He got the most airtime, he stood out amongst the huge crowd of candidates, and his poll numbers were great.

But his most recent performance was a far more subdued affair. He spoke – and grimaced – far less often, and the camera was able to leave him alone when he wasn’t actually speaking. Is this low-key performance the cause or correlation or result of his relative decline in the polls? There’s no way to tell for sure. I say “relative” because he’s been holding reasonably steady at 24 %, give or take, but Dr. Carson has come from less than 6 % to a dead heat with Mr. Trump in that time, so he can no longer bask in the glory of frontrunner status.

But what has happened to the previously fire-breathing, competition-smashing, body-language-crushing mogul? A near-reasonable Trump is no Trump at all. If he becomes more like other candidates, I fearlessly predict he will slide further into the back of the pack and lose the race to Senator Rubio, or Governor Bush, or even Dr. Carson.

Dr. Carson continues to defy the wisdom that TV demands emotional heat.

From a body language perspective, Dr. Carson’s performance is weak and unconvincing, but that doesn’t seem to bother his supporters. Apparently, they like his gentle, almost sleepy, persona.

If he continues to win, I will have to contemplate once again re-writing the body language rulebook. His lack of connection with the audience, his defensive hand gestures, and his low energy should be killing him, but they’re not yet. In body language terms, Carson and Trump couldn’t be any more different. But both are outsiders, and between them, they are winning the loyalty of just about half of the Republican Party. For now. Can it last?

Mr. Bush expected an easier time of it, and it shows.

He is struggling more than anyone expected in the combative arena of the Republican debate free-for-all. Bush in particular finds debating Mr. Trump, who lacks the politesse of a seasoned politician, difficult. Bush looked ill at ease for the first three debates. Only in the most recent debate at the University of Colorado in Boulder did he settled down and become, if not an aggressive debater, at least good enough to hold on to his donors for now.

Senator Rubio, despite his youth – or perhaps because of it – has shown an unexpected flair for human language and good one-liners.

After a rocky start in the first debate, where he looked nervous and sounded unprepared, Mr. Rubio has been able to articulate the frustration of the eroding economics of the middle class in the US without sounding crazy or intemperate like Mr. Trump. His telegenic good looks and youth don’t do him any harm, either. At 44, he ties Governor Jindal and Senator Cruz in the youngest candidate sweeps, and he’s way ahead of either of those two in the polls. He’s found his stride, and a Clinton-Rubio matchup is the prevailing wisdom among political insiders currently.

But take that with the proverbial dose of Washington DC salt – in politics, as the saying goes, a week is a long time.

And what of the Democrats? The race on that side of the divide looked interesting at first, with the cranky-grandpa-arms-flailing-shouting act of Senator Bernie Sanders starting out fast from the start. But his most recent debate, perhaps because of the Paris tragedy and his relative lack of experience in foreign policy, was a weak imitation of his first showing. He’s Clinton’s only real competition, and he appears to be fading.

So Former Secretary of State Clinton appears to have the race taken care of.

Her first debate was strong from the start, and her second was equally assured, in body language terms, aside from a couple of random gaffes that I suspect soon only the insiders will remember. Clinton has owned the stage both times, despite Sanders’ efforts. And only about half as many people watched Saturday’s debate as did the first one, and the second debate was overshadowed by the Paris atrocities.

That problem is affecting the Republican side of the house as well, with 24 million viewers of the first debates declining to under 14 million more recently. That’s still a great audience if you’re talking a CSI episode, but the decline surely shows that voters are losing interest.

Both sides better start to wrap up their respective races.

Our appetite for these debates is not limitless. Soon it will be time to fast-forward ahead and see who wins. My fearless prediction, based on what we know now, and solely on body language chops? Clinton v Rubio, as hard as it is to imagine Bush not going the distance because he seemed so inevitable at the start.