Republican presidential candidate Sen. Marco Rubio, R-Fla., speaks during the first Republican presidential debate at the Quicken Loans Arena Thursday, Aug. 6, 2015, in Cleveland. (AP Photo/John Minchillo)

If some observers were surprised during last week’s Republican debate when Marco Rubio stated firmly that he opposed abortion rights even in the case of rape or incest, it’s probably because he rarely brings up the issue.

But those who know Rubio didn’t hear anything unusual.

The young U.S. senator running for president has held consistent views on abortion rights throughout his career in public office. When he ran for the Senate in 2010, Rubio answered a questionnaire from the National Right to Life Committee by declaring his opposition to abortion, including in the cases of rape and incest (he does believe in an exception for the life of the mother).

He’s always received a 100 percent rating from that group and a zero percent rating on Planned Parenthood Action Fund’s congressional scorecard.

“He has an outstanding pro-life record,” said Douglas Johnson, legislative director at National Right to Life. “I can’t think of a single thing where his record is less than outstanding on issues that concern our organization.”

Yet, now as he navigates the 2016 elections, Rubio’s stance on the charged issue holds new significance as Republicans need to close the gender gap to win national elections. His supporters say there’s been renewed enthusiasm for him after his strong debate performance and argue that his firm anti-abortion rights stance is an asset with conservative primary voters.

Yet Matt Lewis, a conservative columnist for the Daily Caller, wrote this week that he’s worried Rubio handed Democratic frontrunner Hillary Clinton an easy “war on women” attack line at a time when the GOP needs female voters.

“He’s one of the plausible nominees, and no Republican candidate in history has taken the position that he has laid out here,” David Axelrod, an architect of Barack Obama’s 2008 presidential campaign, said in an interview. “I was frankly surprised when he said that.”

Recent GOP presidential nominees from both George Bushes to Mitt Romney were further to the left than Rubio on abortion rights — they supported exceptions for rape and incest. And Jeb Bush, considered Rubio’s greatest rival for the GOP nod, also supports rape and incest exceptions, though Scott Walker goes further and does not support exceptions even for the life of the mother. Current GOP frontrunner, Donald Trump, is against abortion, but supports all three exceptions.

Throughout his five years in the Senate, Rubio has supported, and co-sponsored, legislation that restricts abortion rights for women — but he’s been more of a low-profile persuader than a crusader. Some of the measures he backed included exceptions for rape and incest, and others did not.

He is also part of a group of senators — including several of the other presidential candidates — pushing for a national 20-week abortion ban, and raised his hand to lead the effort in 2013. Anti-abortion rights groups urged him to take on the leadership position, hoping his reputation as a persuasive orator would benefit their message.

His thoughtful way of speaking – a Bill Clintonesque combination of a legal background and natural charisma – has set him apart from the more incendiary Republicans, and helped create his more moderate image. Rubio wants to be viewed as part of a new generation of Republican leaders who can broaden the GOP tent — yet unlike some centrists who move right to appeal to base voters, Rubio is genuinely already very conservative.

And since last week, his answer about abortion rights has created an opening for Democratic groups to attack.

“Even serious GOP presidential contenders know these extreme positions on women’s health won’t fly with a general electorate — that’s why you’ve seen candidates like Rubio try in the past to avoid going into details about where they stand. But this last debate seems to have backed him into a corner,” argued Dawn Laguens, executive vice president of the Planned Parenthood Action Fund, in an e-mail.

Following the debate, Clinton called Rubio’s position “offensive,” “outrageous,” and “deeply troubling.” Others on the left compared him to 2012 Missouri Senate candidate Todd Akin, who said women’s bodies can shut down “legitimate rapes” to avoid pregnancy.

But Alex Conant, a spokesman for Rubio, flipped the script, and said that it was Clinton whose position on abortion was extreme.

“Marco is 100 percent pro-life, always has been, and isn’t going to change now that he’s running for president,” Conant said. “Hillary Clinton has radical abortion positions and we look forward to exposing them.”

Rubio is leaning in to his position with some stronger rhetoric. During the debate, Rubio said that this generation would be viewed as “barbarians” for legalizing the procedure. Days later, he tweeted a photo of a cat with a somewhat obscure point: “Human life won’t become a cat.”

The perception of Rubio as more moderate goes back to the beginning of his career. When he first ran for the Florida legislature in 1999, the Miami Herald wrote in its endorsement of him: “He is pro-life but says that he understands fully that a woman’s right to an abortion is the law.”

Rubio’s friend from those days, Florida state Rep. Dennis Baxley, considered one of the most socially conservative in the state legislature, said Rubio’s position on those issues “is core to how he thinks. Anytime we had ideas on the table to respect life, he was supportive.”

Yet, Rubio has always tried to articulate the message more subtlely.

“I think all of us, Marco included, are afraid of getting pigeonholed on an issue,” Baxley said. So it’s framed more as: “What are you doing to facilitate the success of the young mother … what are you doing for all Floridians to have a better chance?”

In 2005, when he was about to become speaker of the Florida House, Rubio used a temperate tone, telling the Florida Bar News that the way to prevent abortions is “not by harassing people, not by intimidating people, not by stigmatizing people, but by allowing women to understand the options they have…”

A year later, he was widely commended for a 100-point plan modeled off Newt Gingrich’s “Contract for America.” In it, there was no mention of social issues. He dispatched fellow Republicans across Florida to get ideas, which one local news account called an “astute public relations move.”

But later, in 2007, he backed cultural warrior Mike Huckabee for president over more establishment picks like John McCain and Romney. He later brought a bill to the state House floor requiring women who want abortions to first have ultrasounds

In the Senate, Rubio has made his name on issues like immigration, and more recently opposing the restoration of diplomatic relations with Cuba. But he’s also more quietly been an ally to the anti-abortion rights groups.

Since his first term, he has introduced the Child Interstate Abortion Notification Act, which would make it illegal for a minor to cross statelines for an abortion in an effort to circumvent some states’s parental notification laws. When given the opportunity to write his own language, Rubio did not include a rape or incest exception. But he did include an exception to save the life of the mother.

In 2012, as the keynote speaker at the anti-abortion rights Susan B. Anthony List’s annual gala, Rubio said: “The right to life is a fundamental one that trumps virtually any other right that I can imagine.”

“He asked us to remind him of that speech if he ever faltered,” Marjorie Dannenfelser, the group’s president, said. “No reminder has been necessary. He continues to boldly speak out in defense of life, which he has called a definitional issue.”

Sean Sullivan contributed to this story.