Republican presidential candidates Ben Carson and Carly Fiorina (European Pressphoto Agency/Getty)

Retired neurosurgeon Ben Carson and former tech executive Carly Fiorina — novice politicians whose attacks on Democrats have made them conservative stars — declared Monday that they were running for president as Republicans.

Carson, 63, held a slickly produced event in his home town of Detroit, where the candidate took the stage after several musical numbers, including “The Battle Hymn of the Republic” and Eminem’s “Lose Yourself.”

“I’m Ben Carson, and I’m a candidate for president for the United States,” Carson said, before declaring — no longer correctly — “I’m not a politician.” Carson will now visit Texas, where his mother is gravely ill, before flying to Iowa to campaign.

Fiorina, 60, made her announcement in a Web video and an appearance on ABC’s “Good Morning America.” After losing a Senate race in California in 2010, Fiorina has relaunched her political career by lobbing attacks at the Democratic front-runner, former secretary of state Hillary Rodham Clinton.

On Monday, her video began with Fiorina watching Clinton’s own announcement — then raising the remote and turning off the TV.

Republican neurosurgeon Ben Carson hosted a choir singing an Eminem cover and vowed not to be "politically correct" at the event announcing his run for president in 2016. Here are those key moments and more. (AP)

“If you believe that it’s time for citizens to stand up to the political class and say, ‘Enough,’ then join us,” Fiorina said. “We can do this, together.”

Carson and Fiorina led remarkable, pathbreaking lives before politics. But in their short time on the national political stage, both have been defined — and limited — by the same set of skills.

They are masters of the attack line.

Carson, a pioneering black surgeon, began his political rise by attacking President Obama’s health-care law — with Obama sitting nearby — at a prayer breakfast in 2013. Fiorina, a pioneering female executive, has relentlessly criticized the most prominent woman in the race.

Because of who they are, Carson and Fiorina can articulate conservative frustrations with Obama and Clinton while blunting a potent line of Democratic counter­attack: that, if you dig deeply enough, some criticism of Obama and Clinton has its roots in racism or sexism.

If the pair want to do more than disrupt the race, they will have to expand beyond the role of punch-thrower. And they will need to avoid the problems that usually sink nonprofessional politicians running for president: verbal gaffes, rattling skeletons, poor preparation.

Not to mention the tendency to think through sensitive subjects out loud, on camera. “I don’t wander off into those extraneous areas that can be exploited. I have learned that,” Carson said during a TV interview Sunday evening.

Carly Fiorina announces she will seek the 2016 Republican presidential nomination. (CarlyforPresident.com)

With their announcements, Carson and Fiorina officially joined a trio of senators — Ted Cruz of Texas, Rand Paul of Kentucky and Marco Rubio of Florida — in the Republican field. In many polls, the newcomers are behind all three of them. They’re also behind two candidates who aren’t official yet: former Florida governor Jeb Bush and Wisconsin Gov. Scott Walker.

For now, Carson seems like the less long of the two long shots.

In March, a Washington Post-ABC News poll showed him with the support of 6 percent of GOP voters. With the electorate divided among a number of candidates, that puts him in the middle of the pack. In South Carolina and Iowa, that kind of number puts Carson in the top six.

The bad news for Carson is that recent surveys have shown his standing tick down as others have formally announced that they are running.

In his announcement Monday, Carson sought to expand his political persona by returning to his personal story. He was raised by a single mother, graduated from Yale and the University of Michigan’s medical school, and became the youngest director of pediatric neurosurgery at Johns Hopkins Hospital in Baltimore, the first black person to hold the position.

In a video that played before he spoke, Carson’s message seemed to be that, if he became president, he could imbue the country with the qualities that underlie his personal success.

“Healing requires a leader with calm, unwavering resolve,” the video said. “We have the fortitude to heal, the imagination to inspire and the determination to revive our American dream.”

Then Carson took the stage, without notes, and gave a meander­ing speech about his hope for a less-intrusive government, about personal responsibility and about his upbringing in Detroit. “I remember when our favorite drug dealer was killed,” he said at one point.

He also showed the confident, iconoclastic side that has defined his time in the political spotlight. Carson’s tendency to speak his mind has won him some critics — particularly for his assertion that Obama’s health-care law is the “worst thing that has happened in this nation since slavery.”

In an interview after his speech, Carson said that his supporters were too numerous to be denied.

“I continue to travel around five or six states a week,” Carson told The Washington Post in an interview. “And wherever I go there are huge, enthusiastic crowds of people saying, ‘You’re our hope.’ That made me believe that I owe it to those hundreds of thousands, if not millions, of people who feel that way.”

For Fiorina, 60, the first challenge of her campaign will be to raise her poll numbers out of George Pataki territory. She gets only about 1 percent support among Republicans nationally. Even in this race, that’s low.

The good news is that a lot of people don’t know Fiorina yet: About 3 in 5 Republican-leaning voters had no opinion of her in a Monmouth University poll last month. And in a recent swing through Iowa, Fiorina attracted unexpectedly large crowds, more than 100 at some events.

“We have time,” she said with a laugh during a conference call with reporters Monday morning. “There has been greater reception to my candidacy than I think many might have expected. . . . We won’t raise the most money of anyone in the field, for sure, but we’ll raise sufficient money.”

Fiorina is racing to introduce herself to voters with this simple biography: She started her career as a secretary in a small real estate firm, married a former tow-truck driver and worked her way up
to become chief executive of ­Hewlett-Packard.

“It’s only possible in the United States of America for a young woman to start as a secretary and become a CEO and maybe, just maybe, run for the presidency of the United States,” Fiorina said during a forum for potential candidates in Iowa in late April.

Fiorina’s back-story is more complex. Before she was a secretary, she graduated from Stanford University in 1976, with a degree in medieval history and philosophy. She enrolled in law school at UCLA, following in the footsteps of her father, Joseph Tyree Sneed III, a law school professor and federal appeals court judge.

But Fiorina dropped out of law school after one semester and took a job as a secretary at a real estate investment brokerage firm in Palo Alto, across the street from the headquarters of Hewlett-Packard. For two decades, Fiorina did sales, marketing and strategy work for several major telecommunications companies.

In 1999, she became chief executive of Hewlett, making her the first woman to lead such a large corporation. But that pioneering achievement did not end well.

The dot-com boom hurt Hew­lett, and Fiorina was criticized for seeking the public limelight as her company struggled. She was forced out in February 2005. Fiorina received a $21 million severance package.

Scott Clement contributed to this report.