Chris Christie can be loud -- he'll be the first to admit it.

And on Sunday, as the New Jersey governor and Republican presidential hopeful traveled on an Amtrak between Washington and New York, his amplified voice got him into some slight trouble.

Christie bordered the train's quiet car and was kicked off after shouting into his cellphone, according to the website Gawker.

He was also sipping a smoothie.

A statement from the governor's spokesperson, obtained by CNN, confirmed an incident occurred.

Since Christie launched his presidential campaign over the summer, he has failed to gain much traction. He's currently polling toward the bottom of the field.

New Jersey Gov. Chris Christie leveled a strong accusation against President Obama on Sunday, saying the commander in chief and the Black Lives Matter movement are against police officers nationwide.

Christie, a Republican presidential hopeful and former prosecutor, said both Obama and Black Lives Matter, which grew out of protests of police shootings of unarmed black men in recent years, are a part of the “lawlessness” plaguing the country.

“The problem is this, there's lawlessness in this country. The president encourages this lawlessness. He encourages it,” said Christie, on CBS’s “Face the Nation. “He does not support the police, he doesn't back up the police, he justifies Black Lives Matter.”

Christie, who is polling nationally at about 2%, offered no concrete examples of Obama -- the nation’s first black president -- not supporting police.

Christie went on to say the Black Lives Matter movement has called for the murder of police officers.

Nowhere in the group’s policy platforms does it promote violence. When the show’s moderator made that point, Christie was dismissive.

“They've been chanting in the streets for the murder of police officers,” he said.

In a Facebook post in September, Black Lives Matter noted that some conservatives are trying to demonize the group as anti-police.

“We're targeting the brutal system of policing, not individual police,” the group said in the post. A request for comment from members of Black Lives Matter was not immediately returned Sunday.

Last week, in remarks at the White House, Obama lauded the efforts of the movement.

"We as a society, particularly given our history, have to take this seriously," Obama said.

In recent weeks, Black Lives Matter has released a policy platform known as Campaign Zero. Key pillars include beefing up oversight of police departments with civilian review boards and equipping officers with body cameras.

Presidential candidates, including Hillary Rodham Clinton, Bernie Sanders and Jeb Bush, have met privately with Black Lives Matter demonstrators to discuss issues of race and social justice.

Saturday night marked the start of a new and perhaps more contentious phase in the race for the Democratic presidential nomination.

For Sen. Bernie Sanders, in a stronger position than likely even he thought he’d be at this point in the campaign, it was a time to sharpen his argument against Hillary Rodham Clinton. During the Iowa Democratic Party’s Jefferson-Jackson Dinner, an early barometer for the campaigns, he highlighted unpopular policy choices he’d made that were proven more acceptable over time — and also happened to be ones where Clinton or her husband took the politically safer route.

Former Maryland Gov. Martin O’Malley sought to reboot his underdog campaign in a newly narrowed field, casting himself as the candidate of “actions, not words.”

And Clinton, her position as the front-runner newly secure again, flexed the muscle of the massive campaign operation her team is building while presenting herself as ready and more than capable of taking on Republicans in 2016.

Looming above it all was the legacy of President Obama’s own breakout performance at the same dinner eight years ago, the moment his team looks back on as the turning point of his historic campaign.

In 2007, Obama earned credentials that the three Democrats each sought to highlight for themselves Saturday. Sanders embraced Obama’s argument against Clintonian caution — particularly on same-sex marriage and trade — while highlighting the unprecedented response of the grass roots to Sanders’ call for political revolution.

“Eight years ago, all of the political experts talked about how another Democratic candidate for president just couldn’t win. He was unelectable. You remember that guy?” Sanders said of Obama. “I think we are going to prove the pundits wrong again.”

O’Malley made the case for generational change, like Obama, but also stressed his own executive experience and record of delivering on the types of promises he and his rivals are making, including immigration reform and gun restrictions.

“I am clear about my principles; I know where I stand,” O’Malley said.

And in perhaps the only benefit of his underdog status, he was the only candidate to regularly win applause from all corners of the Hy-Vee Hall that hosted the dinner. The Sanders and Clinton cheering sections had been reluctant to cheer for each other’s preferred candidates.

Clinton’s team seemed to be focused on the organizational aspects of the dinner, which Obama’s campaign helped pioneer. She brought in both her husband and pop star Katy Perry to help turn out supporters.

Her own remarks were a freshened-up version of her stump speech, rather than a new argument. Advisors said it was simply a reflection of the fact that her message was working and they were confident in sticking with it, suggesting the new attacking posture of her rivals was a reflection of their view of the state of the race.

It’s a posture that’s likely to play out on the campaign trail in the coming weeks and could make for sharper exchanges ahead of a major candidate forum in South Carolina on Nov. 6, and the second televised debate in Iowa a week later.

Immigration reform has been a key to Donald Trump’s rise to the front of the GOP presidential field.

His rhetoric about building a wall along the U.S.-Mexico border and ending birthright citizenship resonates with conservative Republicans seeking a solution to illegal immigration. An estimated 11 million people are in the country illegally, and Trump wants to deport all of them and allow only some to return, though he’s not detailed the logistics of such an undertaking.

Taken together, the proposals go further than any that have gained traction in Washington in recent years, and that has Trump’s challengers for the GOP nomination calling them a nonstarter.

“What he’s saying now borders on the absurd,” said Florida Sen. Marco Rubio on CNN’s “State of the Union” on Sunday. “He’s going to deport all these people and then he’s going to allow back in the ones that are good. His plan makes no sense.”

Trump’s plan to end birthright citizenship would require a constitutional amendment. Anyone born in the U.S. has been considered a citizen since the 14th Amendment’s adoption in 1868.

Moreover, he’s said that seizing wages that Mexicans in the U.S. send back home would force the country to pay for the wall — a move economists have called unlikely.

Other candidates, such as former Florida Gov. Jeb Bush, have dismissed Trump’s immigration plan as nonsense. Dr. Ben Carson, who has seen a boost in his poll numbers, agrees with Trump about the need for a wall, but for the most part, has remained mum on ending birthright citizenship. He’s noted how many countries in the world do not have birthright citizenship like the United States.

Both Bush and Rubio support granting a path to legal status for those in the country illegally — a moderate position that is not in lockstep with the GOP base.

For Rubio, immigration has been an issue in which the first-term senator has been accused of flip-flopping.

He supported a comprehensive immigration proposal in 2013 that called for a path to citizenship and expanded work visas.

But in the years since, Rubio, who is polling toward the middle of the crowded field of GOP candidates, has said that his support was a mistake and that immigration reform should be done in a more piecemeal approach.

Whether GOP primary voters will allow that to pass will be answered in a few months.

Donald Trump appeared undeterred on Sunday in the face of new polls in Iowa showing him falling behind retired neurosurgeon Ben Carson, stressing that he’s the “unifier” the country needs.

Trump, who has led the crowded Republican field for months, said he’ll bring bipartisanship to Washington at a time of immense polarization.

Speaking on CNN's "State of the Union," Trump focused on the battle last week between Republicans on the House Select Committee on Benghazi and Hillary Rodham Clinton, the front-runner for the Democratic presidential nomination, who testified before the panel for nearly 11 hours.

“The level of hatred between Republicans and Democrats was unbelievable. … I’ve never seen anything like it,” Trump said. “I’m going to unify. This country is totally divided. Barack Obama has divided this country unbelievably. And it’s all, it’s all hatred, what can I tell you. I’ve never seen anything like it. … I’ve gotten along with Democrats and I’ve gotten along with Republicans. And I said, that’s a good thing.”

Trump, whose appeal as a political outsider has helped his candidacy flourish, added that if elected, he’d be a “great unifier for our country.”

For Trump, criticism of both parties is nothing new.

He’s relentlessly assailed GOP rivals, including former Florida Gov. Jeb Bush, for being “low-energy” and focused attention on Clinton as untrustworthy for her use of a private email server while secretary of State.

“You elect Hillary president, you have a country that goes to hell,” he said Friday before several thousand at a rally in Florida.

On Sunday, as a recent Des Moines Register poll showed Carson leading Trump by 9 percentage points in the state, the billionaire businessman turned his attention to Carson.

“We need high-energy people,” Trump told interviewer Jake Tapper. “I think Ben Carson is a very low-energy person. Actually, I think Ben Carson is lower energy than Jeb, if you want to know the truth. We need strong energy.”

Moreover, in recent days, Trump has questioned Carson’s Christian faith — something that’s appealed to evangelical voters in Iowa. Carson is a Seventh-day Adventist.

“I'm Presbyterian. Boy, that’s down the middle of the road folks, in all fairness,” he told the crowd in Florida. “I mean, Seventh-day Adventist, I don’t know about. I just don’t know about.”

Ben Carson, coming under fire from Donald Trump in the Republican presidential race, said Sunday that he would not respond in kind.

"Everybody has their own personality. And if he'd like to do that, that's fine. That's not who I am. And I don't get into the mud pit," Carson said in an interview on NBC's "Meet the Press."

Carson, a retired neurosurgeon, also restated his wish to see virtually all abortions made illegal, saying he does not accept the idea of exceptions for cases of rape or incest.

"I would not be in favor of killing a baby because the baby came about in that way," he said.

Cases in which a woman's life is in danger are an "extraordinarily rare situation," he said. "But if in that very rare situation it occurred, I believe there's room to discuss that."

Carson has moved into the lead in polls of the primary season's first contest, in Iowa, largely because of strong support from evangelical Christians, who make up a large share of Iowa's Republican caucus voters. As he has done so, Trump has started to go after him, taking a swipe Saturday at Carson's Seventh-day Adventist religion.

"I'm Presbyterian. Boy, that's down the middle of the road folks, in all fairness. I mean, Seventh-day Adventist, I don't know about. I just don't know about," Trump said during a campaign rally in Florida.

Over the past two months, Trump has ridiculed several of his rivals in the GOP race, most notably Jeb Bush.

But as Bush has fallen in polls, Trump has signaled that his attention is moving elsewhere.

"I thought Jeb was going to be the front runner. Obviously, he's not, and I'm not going to talk about him so much any more," Trump said in an interview with CNN's Jake Tapper that aired Sunday.

Former President Bill Clinton and singer Katy Perry helped rally supporters of Hillary Rodham Clinton on Saturday ahead of Iowa Democrats' Jefferson-Jackson Dinner.

But eight years ago, Iowa was a battle Hillary Clinton lost to then-Sen. Barack Obama.

Fast-forward to now, when it appears her campaign is taking a page from Obama's campaign. The Times' Michael A. Memoli takes a look.