MANCHESTER, N.H. — Pete Buttigieg came into Friday night's Democratic presidential debate here riding a wave of momentum from Iowa. He walked out facing a new round of nagging questions about his inexperience and his ability to represent the interests of a diverse party.

The first could have more of a direct impact on his chances in this state — where he is running neck and neck with Sen. Bernie Sanders, I-Vt., in recent polling — while the second threatens his viability when the primary calendar turns to states with significant African American and Latino populations.

"The next president of the United States will have to be president of all Americans," Symone Sanders, a top aide to former Vice President Joe Biden, who has led in national polling among black voters, said following the debate. "There was only one candidate on the stage tonight that was ready to do that. Mayor Pete was not that candidate. Joe Biden is ready to do that."

On one level, these are good problems for the former mayor of South Bend, Indiana, to have. He was in the spotlight, open to a new level of scrutiny from ABC's debate moderators and more aggressive attacks from his rivals, because of his success in Monday's Iowa caucuses.

But he also found himself in a political box of his own making.

Buttigieg has held himself out as the candidate who can best bridge the divide between the progressive and the centrist wings of his own party and between the Republican and the Democratic parties. Running on a unity message makes it harder for him to punch back assertively when he comes under fire and that makes him look less ready to go to war with President Donald Trump. That's a lesson most of the other candidates who have positioned themselves between the centrist Biden and the progressive stalwart Sanders already have learned — some of them after they dropped out of the race.

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Buttigieg attributed the number of marijuana arrests going up during his tenure as mayor to an effort to crack down on gang violence in communities of color.

"One of the strategies our community adopted was to target when there were cases when there was gun violence and gang violence, which was slaughtering so many in our community — burying teenagers, disproportionately black teenagers," he said. "We adopted a strategy that said that drug enforcement could be targeted in cases where there was a connection to the most violent group or gang connected to a murder. These things are all connected. But that's the point, so are all the things we need to change, in order for us to prevent violence and remove the effects of systemic racism, not just from criminal justice but from our economy, from health, from housing and from democracy itself."

Asked whether that answer was substantial, Sen. Elizabeth Warren, D-Mass., said: "No."

Buttigieg, who has struggled to gain traction with voters of color, took some hits on social media and among the television punditry.

Former New Jersey Gov. Chris Christie, a Republican, told ABC that Buttigieg looked like a "deer in headlights."

But Rep. Anthony Brown, D-Md., a member of the Congressional Black Caucus and an ally of Buttigieg, said Friday night that there is time for the former mayor to turn things around with voters of color.

"He's got a really good record and story to tell about South Bend," Brown said.

The issue isn't likely to have much resonance in this state, where 93 percent of the residents are white, but Buttigieg's main argument against his three top rivals took a shot from a fourth competitor, Sen. Amy Klobuchar, D-Minn., on Friday.

When Buttigieg's lack of experience has come up, he's turned the question around to portray Sanders, Biden and Warren as creatures of Washington who practice an antiquated version of politics. Democrats need a leader untainted by old ways of thinking to take on Trump, he argues.

But Klobuchar, whose Friday debate performance was roundly praised, flipped that on him.

"We have a newcomer in the White House," she said of Trump, "and look where it got us."

Buttigieg, who has said there's more risk in turning to veterans of Washington than to a neophyte, may need to recalibrate a bit. Then again, maybe not.

Jeff Weaver, a top adviser to Sanders, said Trump's four years in the White House don't make him a better choice for president than Buttigieg.

Any of the Democratic candidates would be "far superior to Donald Trump," Weaver said after the debate.