This article is from the archive of our partner National Journal

Republican presidential candidate Marco Rubio is engaged in a new kind of GOP primary, the one that happens inside the Beltway.

Just hours after a rousing speech from Freedom Tower in Miami Monday evening announcing his intentions to run for the White House, Rubio set off—not to Iowa, not to New Hampshire—but to Washington, D.C., where Secretary of State John Kerry was scheduled to brief senators on the ongoing nuclear negotiations with Iran Tuesday and Senate Foreign Relations Chairman Bob Corker was slated to mark up legislation giving Congress oversight over any deal the administration managed to reach.

While Democratic candidate Hillary Clinton spends her week jaunting around the state of Iowa in the "Scooby van," being chased down by anxious reporters, Rubio's decision to stay in Washington underscores the competing priorities faced by senators looking for a promotion.

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Rubio's experienced backlash before for choosing the campaign trail over congressional duty. A BuzzFeed story last week chronicled how he missed a classified briefing on ISIS and two intelligence committee briefings because he was fundraising in California.

It's not unusual for members of the Senate who are running for president to have to put their ambitions ahead of good attendance.

In November 2007, CNN reported that then-Sen. Barack Obama had missed 80 percent of the votes over a two-month period in the Senate.

Both Cruz and Paul announced their candidacies during the recess, when congressional hearings and votes were already on hold, but Rubio's official bid came just as key foreign policy issues he has been outspoken on—Iran and Cuba—came to a head. So instead of looking to raise his profile in the early-primary states, Rubio's has been doing the best he can in Washington this week to shore up D.C. support.

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On Wednesday, he dropped by the Heritage Foundation to tout his tax plan with Sen. Mike Lee of Utah. It was an opportunity for Rubio to once again recount his family story, to talk with the pundit class about why his newest tax plan ensures a new generation of middle-class Americans.

"We have a chance to replace the jobs we've lost and jobs that paychecks are stagnant in with better paying jobs that provide a higher quality of life and more opportunity for advancement and better pay," Rubio said.

The senator has faced plenty of criticism from conservatives for not recycling standard GOP tax proposals in his own proposal, not reducing the tax burden more on wealthy Americans, and for expanding the child tax credit.

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But at Heritage, Rubio seemed to be after a different kind of endorsement. While the Heritage Foundation itself operates as a nonprofit and does not dole out political endorsements, Mike Needham, the leader of its political operation—Heritage Action—told Politico it plans to release a scorecard for each presidential contender this fall. The outfit is also still considering weighing in on the 2016 Republican primary and endorsing a candidate.

For many conservatives on Capitol Hill including Rubio—who has struggled over the last year to fight back calls that he abandoned conservative principles by negotiating a bipartisan immigration bill—a stamp of approval from the Heritage Foundation could be huge.

While Rubio has not been able to spend the days immediately after his announcement gaining notoriety in the early states, he's still been making inroads. One of the biggest obstacles facing Rubio remains his relationship with the conservative voters who may view him as too moderate a candidate, especially compared to someone like Cruz. But Rubio also earned a surprising amount of support this week from radio host Rush Limbaugh—an influential conservative pundit who has not always been his biggest fan.

"He is instantly likable. He's motivational. He's inspirational in a Reaganesque way because he has that family story, and he relishes telling that story," Limbaugh said.

Rubio might have spent the first days of his candidacy stuck in Washington, D.C., but it appears he has still managed to get his message out without any of the pushback that might have come if the candidate who wants to be seen as tough on foreign policy missed a key markup on Iran legislation. And now he gets to get out of town: first to Boston and New York, and then to the first primary state for New Hampshire's Republican Leadership Summit.

This article is from the archive of our partner National Journal.

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