Marco Rubio is running a presidential campaign marked by precision, caution and discipline -- so much so that the Florida senator delivers the exact same speech, jokes, quips and one-liners wherever he goes.

When he addresses the media, his aides select the reporters who can ask questions, often shutting down follow-ups. During media interviews and presidential debates, Rubio is quick to fall back on the same script that he often delivers before GOP audiences in New Hampshire and Iowa.

Rubio speaks to an aide on Capitol Hill as he arrives for the weekly Senate Republican Policy Committee luncheon in September 2013.

Rubio speaks to an aide on Capitol Hill as he arrives for the weekly Senate Republican Policy Committee luncheon in September 2013.

Rubio returns to the Capitol after meeting with Obama and other Republican leaders about the government shutdown in October 2013.

Rubio returns to the Capitol after meeting with Obama and other Republican leaders about the government shutdown in October 2013.

Rubio, center, speaks to members of the media as Sen. Ron Johnson, left, and Rep. Ron DeSantis listen during a news conference on Capitol Hill in October 2013.

Rubio, center, speaks to members of the media as Sen. Ron Johnson, left, and Rep. Ron DeSantis listen during a news conference on Capitol Hill in October 2013.

Rubio confers with McCain as U.S. Ambassador to Syria Robert Ford testifies before the Senate Foreign Relations Committee in October 2013.

Rubio confers with McCain as U.S. Ambassador to Syria Robert Ford testifies before the Senate Foreign Relations Committee in October 2013.

Rubio speaks in November 2013 during a campaign stop for Virginia Attorney General Ken Cuccinelli, the Republican candidate for governor of Virginia.

Rubio speaks in November 2013 during a campaign stop for Virginia Attorney General Ken Cuccinelli, the Republican candidate for governor of Virginia.

From left, Sens. Cory Booker, Rubio, Kristen Gillibrand and John McCain wait for Obama to deliver the State of the Union address in January 2014.

From left, Sens. Cory Booker, Rubio, Kristen Gillibrand and John McCain wait for Obama to deliver the State of the Union address in January 2014.

Rubio, left, is greeted as he arrives at a restaurant in Doral in February 2014.

Rubio, left, is greeted as he arrives at a restaurant in Doral in February 2014.

Rubio checks his phone in March as he arrives for a Capitol Hill news conference to introduce a proposal for an overhaul of the tax code.

Rubio checks his phone in March as he arrives for a Capitol Hill news conference to introduce a proposal for an overhaul of the tax code.

Rubio speaks to the media in front of a wall dedicated to the victims of the violence in Venezuela as he shows support for the Venezuelan community at a restaurant in Doral, Florida, in April 2014.

Rubio speaks to the media in front of a wall dedicated to the victims of the violence in Venezuela as he shows support for the Venezuelan community at a restaurant in Doral, Florida, in April 2014.

Rubio talks to aides in December before speaking on President Barack Obama's announcement about revising policies on U.S.-Cuba relations.

Rubio talks to aides in December before speaking on President Barack Obama's announcement about revising policies on U.S.-Cuba relations.

Rubio speaks with the media after delivering remarks during the graduation of small business owners from the Goldman Sachs 10,000 Small Businesses program held in Miami in February.

Rubio speaks with the media after delivering remarks during the graduation of small business owners from the Goldman Sachs 10,000 Small Businesses program held in Miami in February.

Rubio, center, arrives in the House chamber ahead of Israeli Prime Minister Benjamin Netanyahu's address to a joint meeting of the U.S. Congress in March.

Rubio, center, arrives in the House chamber ahead of Israeli Prime Minister Benjamin Netanyahu's address to a joint meeting of the U.S. Congress in March.

Sen. Mike Lee, left, and Rubio talk before a news conference to introduce their proposal for an overhaul of the tax code in March.

Sen. Mike Lee, left, and Rubio talk before a news conference to introduce their proposal for an overhaul of the tax code in March.

Florida Sen. Marco Rubio speaks in October 2013 at the Values Voter Summit, held by the Family Research Council in Washington.

Florida Sen. Marco Rubio speaks in October 2013 at the Values Voter Summit, held by the Family Research Council in Washington.

His campaign makes sure every room is packed. Lately, that's because an overflow audience is interested in hearing from the surging candidate. But other times his aides have cut the room in half with drapes, ensuring it's a standing-room-only crowd.

If Trump is the kind of candidate who will say and do virtually everything that's on his mind at that moment, Rubio is the complete opposite: He rarely deviates.

To some, it's the kind of thing that makes them eager to back Rubio: He's unlikely to make a mistake that could change the trajectory of the presidential race and cause problems down the ticket. And he's hardly the lone candidate in the field who stays relentlessly on message (See Ted Cruz).

Yet, to rivals, it's exactly why the GOP shouldn't nominate him: They say it shows a rehearsed candidate who will crumble in a general election at a time when voters are looking for authenticity.

"His 60-second memorized speeches all of which we've heard over and over and over again are getting stale and tired," New Jersey Gov. Chris Christie said Wednesday on Fox News. "Sen. Rubio needs to come up with some new material and needs to start answering questions. The boy needs to come out of the bubble."

Rubio's strategy and performance is under increased scrutiny following his stronger-than-anticipated third place finish in the Iowa caucuses. A CNN/WMUR released Thursday found Rubio in second place heading into next Tuesday's New Hampshire primary, trailing Donald Trump 29% to 18%.

This week, Rubio defended his style of campaigning and called Christie's attack "silly."

Asked by CNN why he gives the same remarks wherever he goes, Rubio said here in Laconia: "Because it's my message. It's the reason why I'm running for president."

Staying on script

Indeed, Rubio is hardly the only presidential candidate who hews to the same script. Cruz, the Texas Republican, often does the same -- even replicating the same dramatic pause in between comments to voters and the media. In his stump speeches, however, Cruz does often discuss some news developments into his remarks, including to take whacks at Trump, something Rubio rarely does.

Christie recycles jokes on issues ranging from Social Security to college affordability and repeats the same story about 9/11. But his speeches are far more free-flowing and he changes up the topic on a given day.

Yet message discipline can be a good thing on the trail. George W. Bush and Barack Obama both kept to the same stump speeches, and both later became presidents.

Rubio delivers his stump speech by memory -- no teleprompter, no notes. He speaks quickly and authoritatively on a range of subjects. The 44-year-old Cuban American speaks soaringly in generational terms, saying it's time for a "new American century," praising the U.S. for being a country where his under-priveleged family could succeed.

He hits on all issues that appeal to conservative Republicans -- his faith in God, demand to repeal Obamacare, promise to end Obama's regulations, vow to secure the border and calls to rebuild the military. He says the "establishment" didn't want him to run for Senate in 2010 or now in 2016. And he repeatedly says how eager he is to take on Hillary Clinton in November.

"She's disqualified from being commander-in-chief," Rubio says in nearly every stump speech, prompting applause wherever he goes.

To virtually every crowd he speaks with, Rubio says that Clinton is scared of him but he adds, "I cannot wait to run against her," as he said Thursday in Manchester, N.H. Nearly every one cheers.

He consistently talks tough on national security, saying he would send terrorism suspects on a "one-way ticket to Guantanamo Bay." And he says that the world is a "safer place" when America has the "strongest military" in the world.

Even as immigration is a liability for him with some voters, he takes a hardline on the issue in every stump speech.

"When I'm president, sanctuary cities are going to lose their federal funding," Rubio said in Cedar Rapids, Iowa, last month, and he did in New Hampshire this week, as well.

Beyond the red meat, Rubio uses the same jokes and quips repeatedly. He talks about how he racked up student loans and paid them off from sales of his book, "An American Son."

"Now available in paperback," he said in West Des Moines, Iowa, last week -- and the room erupted in a laughter. He did the same this week in Exeter, N.H., last month in Pella, Iowa and here in Laconia -- not to mention virtually everywhere else.

"I know you have a lot of choices," Rubio often says, as he did Thursday in Manchester. "One out of 8 Republicans are running for president -- that's a lot of people." The crowd laughed.

He often talks about his critics on the campaign trail, but he has this quip: "I'll cut their taxes too," something he said on virtually every stop last month and repeatedly this week.

And one of his biggest laugh lines is when he talks about Bernie Sanders -- "that dude is a socialist," he often says, with the common refrain that the Vermont independent would be a good president -- "of Sweden."

Even when he meets voters on the trail, he falls back on lines he often delivers in speeches and in debates. At a debate in November, Rubio said, "We need more welders and less philosophers."

When he met a group of Harvard students majoring in Greek philosophy at a Manchester diner earlier this week, Rubio quipped: "You're going to make a heck of a welder."

But many voters don't seem to notice -- or really care.

"I think they all do it," said Edward Cyr, 65, an undecided New Hampshire voter who works in the health care industry. "It's the same speech but it's a new group of people."

Rubio's media handling

Christie has lashed Rubio for not answering questions, but the senator does take about 20 to 30 minutes worth of questions from voters during each townhall event. And Rubio campaign spokesman Alex Conant said that the senator does more media interviews than "any other candidate."

But there's little doubt that Rubio has grown far more cautious in his interactions with the media since becoming a presidential candidate, as past senators-turned-presidential candidates have as well.

Rubio used to freely walk about the Capitol, holding court with reporters pressing him on a wide range of issues. Since becoming a candidate last year, on the days he does return to the Capitol, he ignores reporters who try to press him -- much the way Hillary Clinton did when she was a senator. But Cruz and Rand Paul when he was a candidate, still respond to reporters' questions, even if they try to limit them.

More recently, Rubio has been holding one media availability per day on the campaign trail, which typically last around seven minutes. He turns to a press aide who will select the questioner. A Rubio official said the senator does this to ensure he can answer questions from as many outlets as possible. But it is a practice most campaigns don't replicate -- though Clinton's does -- and effectively serves to limit the ability of reporters seeking to pin down the fast-talking senator.

Christie lashed out at Rubio for this practice.

"By the way, he acts like the King of England," Christie said. "He has a press secretary stand next to him and preselect which reporters get to ask him questions. This is a guy who has been protected and coddled his entire political career."

Question at town halls

After his stump speech, Rubio lets voters ask him questions -- and occasionally a voter asks him a tough question. Here in Laconia, a voter pressed Rubio for changing his position on letting undocumented immigrants obtain citizenship -- or "amnesty."

"You changed your stance and you sponsored an amnesty bill," the voter said.

Rubio gave a long answer detailing his views on the complex issue, saying that nothing can be done first now without securing the border, arguing that Obama had poisoned the issue by acting unilaterally and saying he tried to make the Senate bill in 2013 more conservative. He insisted the Senate bill was not tantamount to "amnesty."

"I tried to make a difference in a Senate controlled by Democrats," he said.

Through his explanation, Rubio was able to win over skeptics -- and applause from a conservative audience.

His rivals aren't buying it.

"Marco Rubio is a gifted politician, but his whole life has been around his ambitions," former Florida Gov. Jeb Bush said on MSNBC. "And he's gifted. He can turn a phrase really well. But what has he done?"