But Rubio might also find himself in a rhetorical thicket as result of his remarks. In an interview with Fox News in March, Rubio said he didn't think it was a mistake to go to war in Iraq.
"I don't believe it was. The world is a better place because Saddam Hussein doesn't run Iraq," said Rubio.
In his Wednesday speech, referencing the faulty intelligence that wrongly said that Iraq had weapons of mass destruction, Rubio said: "I don't think the Congress would have voted in favor of the authorization."
While the question Rubio faced on Fox News and the one he faced Wednesday were not identical, his answers appeared to express different overarching takes on whether the invasion was justified.
Rubio made his latest remarks in a question-and-answer session after his speech here at the Council on Foreign Relations. They came after Jeb Bush sent conflicting signals in recent media interviews about whether he would have invaded Iraq knowing what is known now.
The address was Rubio's first major policy speech since kicking his presidential campaign last month.
In his remarks, Rubio took sharp aim at President Obama, accusing the the president of implementing policies that have have led to a world "far more dangerous" than when he took office. He also looped Democratic front-runner Hillary Rodham Clinton, Obama's first secretary of state, into his critique.
Blasting Obama's policies across the globe from Cuba to Iran and Russia, Rubio argued that the president has greatly diminished America's might. But in outlining his own positions, which together he dubbed "The Rubio Doctrine," Rubio was nonspecific, outlining three very general pillars: "American strength," "protection of the American economy in a globalized world" and "moral clarity regarding America’s core values."
"This deterioration of our physical and ideological strength has led to a world far more dangerous than when President Obama entered office," said Rubio.
Rubio also said that while two-state solution in the Middle East is the "ideal outcome," the conditions for such an arrangement "at this moment do not exist."
The senator's remarks which he published on the Web site Medium in advance of delivering them, illustrated how he has become much more critical of Obama and has tacked to the right on foreign policy in the last few years.
The Florida senator started his speech quoting John F. Kennedy's speech at the Fort Worth Chamber of Commerce the day he was assassinated and used that to criticize the president.
“I am confident, as I look to the future, that our chances for security, our chances for peace, are better than they have been in the past. And the reason is because we are stronger. And with that strength is a determination to not only maintain the peace, but also the vital interests of the United States. To that great cause, Texas and the United States are committed," said Rubio, citing Kennedy.
Kennedy, said Rubio, "understood what our current president does not: that American Strength is a means of preventing war, not promoting it. And that weakness, on the other hand, is the friend of danger and the enemy of peace."
Rubio reiterated his opposition to the Iranian nuclear deal the Obama administration has been negotiating as well as his decision to normalize relations with Cuba. Rubio's parents are Cuban immigrants.
Rubio took limited but pointed aim at former secretary of state Hillary Rodham Clinton, the Democratic front-runner, calling her "ineffective at best and dangerously negligent at worst."
"The stakes of tomorrow are too high to look to the failed leadership of yesterday," Rubio said of Clinton.
Rubio's remarks marked a shift rightward from positions he took earlier in his Senate career.
When Rubio spoke at Brookings Institution in 2012, however, he staked out what The Washington Post reported was a "middle ground" on foreign policy. In those remarks, he called for bipartisanship and more American “leadership” in the world, lobbing few direct barbs at the president.
In his speech Wednesday, Rubio said his "first priority" as president would be to "adequately fund our military. This would be a priority even in times of peace and stability, though the world today is neither." Earlier this year, Rubio pushed a plan to beef up defense spending in the budget but without offsets in other areas.
But in the past, he has advocated offsetting such spending increases with cuts.
One area where Rubio agreed with Obama was on trade. He called on Congress to give him authority to complete a multi-national trade agreement that has faced resistance from some Democrats.
"It is more important than ever that Congress give the President Trade Promotion Authority so we can finalize the Trans-Pacific Partnership and the Transatlantic Trade and Investment Partnership," Rubio said. "These agreements will create millions of jobs and cement U.S. strategic partnerships in Asia, South America, and Europe."