Seven minutes. Four questions. One plum chance for Marco Rubio to lay into his top competition in the Republican presidential race.

But Rubio held his fire. “I like John Kasich,” he told a group of reporters here. He said he will only hit Donald Trump hard “when the time comes.” Chris Christie’s insults earned only a three-second rebuttal. He declined to say whether he expected to finish off Jeb Bush.

“I’m not running against any of the other candidates in this race,” Rubio said. “I am running for president.”

He’s only in second or third place in the polls, but Rubio is campaigning like a front-runner. As his rivals sling mud at him and each other, Rubio — who finished a solid third in Iowa and is climbing here in the Granite State — is mostly content talking about himself and avoiding combat with the other Republicans.

The strategy reflects the Rubio team’s belief that the New Hampshire primary could be the moment when he begins consolidating mainstream Republican support. It also highlights his aversion to taking on Trump before the field narrows. Slamming the other mainstream candidates could alienate their backers and give the underdogs the attention they are craving.

PITTSFIELD, NH- FEBRUARY 3: Senator Marco Rubio spoke to employees at the Globe Manufacturing business in Pittsfield, New Hampshire on Wednesday, February 3, 2016.(Photo by John Tully/For The Washington Post) (John Tully/For the Washington Post)

His campaign says Rubio is not running any New Hampshire TV ads attacking his opponents. But a pro-Rubio super PAC has been doing the dirty work for the senator from Florida, hitting them with well-funded commercials and freeing him to stay positive.

In town halls, rallies and meet-and-greets this week, Rubio attracted bigger and more assorted crowds than earlier in the contest. He is auditioning as the strongest Republican for the general election and the one most capable of stitching together the different parts of the GOP.

“If you nominate me, I will unite us,” Rubio said in Exeter on Tuesday night. “I will grow this movement. We will win this election.”

[His rivals say the same thing in different ways: Marco Rubio is weak.]

Polls show that Trump holds a wide lead in New Hampshire, with the rest of the field bunched together. Yet Rubio is avoiding a direct confrontation with the brash mogul.

Asked during a Wednesday town hall in Bow about Trump’s mocking a disabled New York Times reporter, Rubio said, “I think we all obviously not just disagree with it but find it distasteful.” Then he quickly moved on.

His most direct shot of the day at Trump came when he was inspecting his tie during a stop at a company that manufactures gear for firefighters. But even then it was playful.

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“It’s not a Trump tie — they make those in China,” Rubio said.

Rubio’s strategists see nothing to be gained by engaging in a war of words with Trump until the field narrows, since no candidate has so far been able to claim lasting success fighting him.

“When the time comes and it’s appropriate, we’ll do so,” Rubio told reporters when asked about taking on Trump more forcefully.

For now, Rubio’s anti-Trump messaging has been more passive, saying that “anger is not a plan.”

Rubio has been more willing to engage Christie, Kasich and Bush, who must do well in New Hampshire to stand a realistic chance of competing for the nomination. Recent polls show Rubio leading them in the state, but not by a wide margin.

The candidate Rubio has hit hardest is Sen. Ted Cruz (Tex.), whom his advisers see as a competitor for many of the same voters. Cruz and his campaign have shown a “willingness to say or do anything” to win, Rubio said.

[Rubio’s summer of ’90: An arrest, then newfound purpose]

Rubio’s growing crowds have been welcome news for his campaign, but there have been some awkward moments. A big and boisterous audience cheered Rubio as he entered an Exeter rally — only to have to wait for him to do a TV interview there before he would address them, frustrating some attendees. A day later, he abruptly paused meeting supporters waiting in a long line so he could do another television appearance.

Rubio’s unity pitch is attracting a more diverse slate of Republicans to his events — and sometimes their views are at odds with one another. At a town hall here in Laconia on Wednesday, Rubio was asked two questions about immigration from opposing perspectives.

One man explained that he employs an undocumented immigrant named Fernando who otherwise obeys the laws. The man said he wanted to figure out a way to “legitimize” people like Fernando.

Rubio said he sympathized with Fernando’s story, but “I also sympathize with the American people, who have to bear the burden of people coming into this country illegally.”

Vince Merola, 77, of Wolfeboro, asked Rubio why he joined the bipartisan “Gang of Eight” that pushed comprehensive immigration reform after running for the Senate opposing “amnesty.”

Rubio denied that he ever went back on his word to oppose “blanket amnesty.” But Merola wasn’t swayed.

“I think he means what he’s saying right now. But will he cave when the party tells him ‘We can’t do that, we’ll lose votes,’ ” wondered Merola, who is leaning toward supporting Cruz.

As Rubio’s support grows, his team will also confront the challenge of preparing a large roster of surrogates to give him crisp support. In a painful Thursday interview with MSNBC, new backer Rick Santorum struggled to point to any major accomplishments Rubio achieved in the Senate.

Saturday’s debate, which will effectively be the last chance to reach a wide audience before Tuesday’s vote, is expected to be nasty. For Christie, Kasich and Bush, in particular, it could be the last real chance to prevent their supporters from straying to Rubio.

Rubio is bracing for a ferocious give and take. He will not be able to avoid a confrontation the way he has on the campaign trail. In Pittsfield, he tried on a firefighter's jacket after a town hall, aware of the looming clash.

“I may have to wear this at the debate,” he said.