HOOKSETT, NH — Marco Rubio on Tuesday sought to frame himself as the only Republican presidential candidate capable of confronting America's national security challenges in a speech that took sharp aim at his primary opponents as "isolationists…more passionate about weakening our military and intelligence capabilities than about destroying our enemies."
"Words and political stunts cannot ensure our security. ISIS cannot be filibustered," Rubio said at an American Legion in Hooksett, New Hampshire.
Coming just one month out from the Iowa caucuses and about five weeks out from the New Hampshire primary, Rubio sought to frame the GOP primary contest solely on national security grounds and pitch himself as the only sober realist in the field.
He peppered the speech with veiled references to his GOP primary opponents, knocking Ted Cruz, Donald Trump and Rand Paul's stances on various issues.
"If ISIS had lobbyists in Washington, they would have spent millions to support the anti-Intelligence law that was just passed with the help of some Republicans now running for president," he said, a reference to the USA Freedom Act, which reigned in government surveillance programs and had the support of both Cruz and Paul.
His charge, too, against "isolationists" in the party is sure to reignite a long-simmering feud between Rubio and Cruz, who appear to be on a collision course for the nomination heading into the final month before the early primary contests start.
Cruz has embraced a more cautious approach to foreign conflicts, charging that previous American-led efforts to overthrow Middle Eastern dictators created vacuums that contributed to the rise of terrorist groups like ISIS.
Rubio, meanwhile, has established himself as a staunch hawk, declaring Assad's overthrow to be a necessary prerequisite to defeating ISIS in the region. And the speech is sure to reignite the longstanding feud between the two, which had cooled somewhat while the two took a break from the campaign trail over the holidays.
Rubio also dismissed "Republican candidates who propose that rulers like Assad and Putin should be partners of the United States," a knock on Trump, who's drawn the praise of the Russian leader and has said he'd "get along fine" with him.
Though the topic of the speech was foreign policy, the aim was politics. Rubio has yet to post a lead in polling of any of the early primary states, and remains locked in a close fight for second with Sen. Ted Cruz in most New Hampshire polling. But his aides believe his strength and fluency on national security issues can help catapult him to the front of the pack in the primary race.
Rubio characterized himself as the only candidate in the GOP presidential field "with a record of leadership and judgment."
"The job is not described in the Constitution as "entertainer in chief" or "commentator in chief" or even, frankly, "economist in chief." It is described as Commander in Chief. If you can't be bothered to offer specifics on how you will perform that job, then you don't deserve that job," he said.
He told supporters Tuesday he was "asking for your vote" to help America "take a turn back toward strength."
Rubio also used the aggressive speech to make a general election case, indicting both President Obama and former Secretary of State on foreign policy.
"Barack Obama has deliberately weakened America. He has made an intentional effort to humble us back to size," Rubio said. Clinton, meanwhile, is both "incompetent" and a "liar," Rubio said.
"Not only is Hillary Clinton incompetent, she's also a liar…She lied to our faces" in saying the attacks on the U.S. consulate in Benghazi, Libya were due to an anti-Muslim video, he added.
Rubio pledged: "If I am our nominee, voters will be reminded of it time and time again."
The speech, his first foreign-policy-focused address since a November 5 speech in New Hampshire, caps off a two-day swing through the Granite State before Rubio heads to Iowa Tuesday afternoon.
This story originally appeared on NBCNews.com