MIAMI, FL – Party Chairman Reince Preibus stepped onto the stage before the debate and directed the audience to unite behind whichever of the four debaters would become the Republican nominee, because “can we agree that any one of them would be a world better than Hillary Clinton or a socialist, Bernie Sanders?” The responding applause was quite audible, though not thunderous.

It seems that the candidates were the ones who heard Preibus’ message, because for the most part – despite incessant prodding by the CNN panel – they refrained from cheap shots toward one another. In fact, were the focus not on destroying ISIS and ending illegal entry and stay in the United States, the debate was so civil and so issues-substantive that one might have thought it was a verbal squabble among Democrats.

Donald Trump was perhaps more restrained than ever, resisting the urge to hit below the belt, and emphasizing unifying the party. He also reassured the Republican audience that “I haven’t even started on Hillary yet.”

Ted Cruz was probably the most directly combative of the four, pointing out that Trump was part of the establishment he now rails against, but even he played by the rules and didn’t interrupt. In general, none of the four candidates talked over each other, or over the panelists.

Marco Rubio had a strong debate, perhaps the strongest of the evening, reverting to what gave his campaign momentum to begin with, before he decided to trade cheap shots with Trump, which arguably led to his single-digit dismal performance in last week’s primaries.

John Kasich, who benefits the most when the other Republican candidates engage in a figurative junior high school cafeteria foodfight, could not capitalize at this debate, because his counterparts didn’t look bad enough for him to stand out as looking good.

Kasich, in fact, probably had the least impressive debate of the four, which might help Trump beat him in Ohio and end the governor’s presidential ambitions.

Cruz did not hurt himself, but didn’t help himself either. He probably holds on to the undiluted conservatives, but doesn’t add many new supporters.

Rubio and Trump were the sharpest of all, with Trump appearing presidential instead of petty, unifying instead of polarizing. Rubio sounded sharp, passionate, and knowledgeable. He might have had the best night, by a hair, with Trump coming in second.

In the long run, Rubio may have helped himself slightly, and still has an outside chance to upset Trump in Florida. But, if not, then Rubio’s campaign is over and Trump should be able to ride out the Cruz barrage to the 1237 delegates needed for the nomination.