March 5, 2016 Sen. Marco Rubio speaks at the Conservative Political Action Conference (CPAC) at the Gaylord National Resort & Convention Center in National Harbor, Md. Amanda Voisard/For the Washington Post

The U.S. senator from Florida is vying for the Republican presidential nomination.

The senator from Florida is among the candidates vying for the Republican presidential nomination.

The senator from Florida is among the candidates vying for the Republican presidential nomination.

Marco Rubio is in an enviable position among mainstream Republican presidential candidates after his strong finish in Iowa. Yet the man is running scared.

The young Floridian is stumping through New Hampshire as if he’s campaigning to win the Cautious Caucus. He gives the same speech everywhere. The most tightly managed candidate in the race, he shuns risk and appears to live in mortal terror of mentioning the man who dominates the race.

At a town hall event here in central New Hampshire on Wednesday morning, Rubio, as usual, didn’t mention Donald Trump in his speech. But the first questioner, a businesswoman, practically begged the candidate to trash Trump, asking him to comment on Trump’s “very definite views” of the disabled, including calling people “stupid” and attempting to remove disabled veterans from one of his properties.

Rubio demurred, saying only that he had already called out “Donald” for his “distasteful” mocking of a disabled reporter at an event. He then dropped the Trump talk and moved on.

Rival Chris Christie mocked Rubio on Tuesday as “the boy in the bubble” managed by his “handlers.” This criticism apparently smoked Rubio out, because he took a few questions from reporters before his event in Laconia, N.H., on Wednesday afternoon.

Speaking in front of an American flag in Bow, N.H., Republican presidential candidate Marco Rubio said the GOP needs a candidate who can "unify" the party. (Reuters)

The first questioner noted that Rubio had poked other candidates, “but not Mr. Trump. Why?”

“Donald hasn’t really outlined any position on policies,” Rubio reasoned. “So when the time comes and it’s appropriate, we’ll do so.”

“Why do you deliver the same speech wherever you go?” the second questioner asked.

“’Cause it’s my message,” he said. “It’s the reason I’m running for president.”

Rubio’s determination not to be taken off of this bland message, or to engage Trump, may give the impression that he is above the fray. But it also can make him look weak and callow.

While other candidates, particularly Jeb Bush, have denounced Trump’s outrages, Rubio and allied groups have spent upward of $30 million on ads so far — some of it targeting Bush, Christie and Ted Cruz, but none of it targeting Trump. Rubio has mentioned Trump a couple of times on Twitter. In debates, he has frequently deflects questions about the mogul.

After the December debate, in which Rubio declined a chance to take on Trump’s proposed ban on Muslims entering the country, Fox News asked Rubio why he hadn’t gone after Trump. Rubio said he wasn’t “going to spend a valuable 75 seconds on a debate stage talking about something that’s never going to happen.”

Likewise, asked to comment on Trump’s qualifications as a conservative, Rubio said that the billionaire is “running as someone who’s a populist who’s upset about the direction of this country, as am I, as are millions of Americans.”

On other occasions, Rubio declined to talk about Trump’s mosque-closing ideas (“well, I think we need to target radicalism”) and Trump’s plan for mass deportation of illegal immigrants (both sides “have points to make here that are valid”).

Asked back in September whether he would engage Trump, Rubio replied: “No, I’m ready to talk about who I am and why I’m running.”

It’s not as if Trump returns the politeness. Ann Coulter, warming up a Trump crowd Tuesday night, called Rubio a “Cuban boy” who “wears high heels” and has “big ears.” (Ever-cautious Rubio, ridiculed last month for wearing “booties” with thick heels, quickly retired the offending footwear.)

Rubio’s strong Iowa finish has brought new attention — and overcapacity crowds — in New Hampshire. But the would-be supporters are greeted by a robot.

The closest Rubio gets to Trump in his stump speech is observing, as he did here in Bow, that “you have a right to be angry, but anger is not a plan. What exactly do you want to do?” Or, as he put it in Laconia a few hours later: “Anger is not a plan. Frustration is not a plan. You have a right to be frustrated. You have a right to be angry. . . . But what exactly are you going to do about it?”

Voters’ questions, rather than spurring spontaneity, inspire more caution. Asked Wednesday what he’d do about the millions of illegal immigrants who otherwise haven’t broken any law, Rubio said, “We’ll figure something out.”

The logic behind Rubio’s candidacy, recited in his speeches, is that, as he put it in Bow: “I give us the best chance to win, and if you don’t believe me, ask a Democrat. They do not want to run against me.” Or, as he said in Laconia: “If I’m our nominee, we will win, and the Democrats know this. They do not want to run against me.”

If he keeps playing the boy in the bubble, they may reconsider.

Twitter: @Milbank

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