Rep. Mario Diaz-Balart is not a quiet man. The gregarious Florida Republican, known for sudden eruptions of laughter and dramatic gesticulations, is hard to miss in a crowd. But when it comes to legislating, the seven-term lawmaker blends in, working methodically, usually behind the scenes, to put his stamp on policy.

That’s how the son of Cuban exiles has become one of the Obama administration’s biggest obstacles to normalizing relations with the communist nation 90 miles south of Florida.

President Barack Obama’s Cuba initiative hits close to home for the Miami lawmaker — his storied political family was forced to abandon the island after Fidel Castro’s 1959 takeover.

Diaz-Balart, born in Fort Lauderdale, has spoken out for years against corruption and human-rights abuses in Cuba, but Obama’s recent overtures have added urgency to his voice and the voices of other lawmakers with family or cultural ties to the island.

While 2016 presidential contenders such as Sens. Marco Rubio, R-Fla., and Ted Cruz, R-Texas, have railed against the Cuba thaw on camera, Diaz-Balart is quietly using his position as a House appropriations subcommittee chairman to block spending on the president’s initiatives, inserting language in bills before they’re marked up by the full panel or considered on the chamber floor and thwarting (so far) Obama allies in the House who support normalization.

Two weeks ago, Democrats tried and failed to remove Diaz-Balart language in the Commerce-Justice-Science Appropriations bill barring exports to Cuba if the Cuban military is involved. A few days later, lawmakers were unable to strip out a provision prohibiting airline and cruise ship service to Cuba.

Diaz-Balart was particularly pleased with the latter vote: That was on the bill to fund the departments of Transportation and Housing and Urban Development, which came out of his subcommittee during his first term as a “cardinal.”

And while he wouldn’t offer details, he assured CQ Roll Call he has plans for riders in other upcoming spending bills.

Recently, the Appropriations Committee released its fiscal 2016 Financial Services-General Government spending measure, which bans financial transactions with the Cuban military and intelligence service and limits education-exchange travel.

Asked whether those provisions came from him, Diaz-Balart just smiled.

He’s tackling his Cuba mission the same way he’s gone about everything else in his congressional career, most recently and notably his Sisyphean attempt to formally introduce a comprehensive immigration overhaul effort.

From 2013 to 2014, Diaz-Balart toiled for months on a secret immigration bill, working with both sides, shopping a PowerPoint presentation, hiring pollsters to study how certain provisions would play in districts around the country. People knew he had a bill but few knew the extent of his efforts until much later — after it became clear the narrow window to tackle the issue had come and gone. He didn’t want to go public until the bill was ready, until it stood a chance of passage.

His pursuit of Cuba policy riders in appropriations bills is much less cloak-and-dagger, but he’s following similar guidelines.

“You have to do it in a way that’s real,” he explained. “You can make a statement through the appropriations process, or you can actually try to get things done through the appropriations process — and the latter is what I’m attempting to do.”

The fiscal 2016 State and Foreign Operations spending bill has a rider restricting the use of funds to open an embassy in Cuba. Though clearly Diaz-Balart would support the restriction, he wouldn’t take credit for the language, suggesting it was not what he had in mind when he talked about the best ways for a Republican Congress to oppose a Democratic president.

“It’s gotta be something that can get some bipartisan support,” he said, pointing out that Democrats, albeit in small numbers, joined Republicans in backing his Cuba language in the C-J-S and T-HUD measures.

This is all he wanted from the first moment he arrived on Capitol Hill, he said. A former Appropriations Committee chairman in the Florida State Legislature, he spent his first eight years in Congress trying to get a seat on the House’s prestigious panel. He finally got the chance in 2010, when Republicans took control.

At that point, he had a decision to make: Stay on Transportation and Infrastructure, where he was poised to become a subcommittee chairman, or become a junior member of the Appropriations Committee.

The choice, he said, was easy.

“My staff thought I was crazy,” he recalled. “They said, ‘You want to go be a peon on Appropriations when you could be the chairman of a pretty good subcommittee?’”

As it turned out, Republican appropriators left at a faster clip than expected — it was only four years before Diaz-Balart had an opening to be a subcommittee chairman on the committee of his dreams.

Even before, he said, he was using appropriations bills to advance his priorities. “When I was in the state Legislature, I stopped filing bills,” he said. “I’ve done that here, too.”

Since becoming an appropriator, he’s introduced just seven bills, including T-HUD this year.

He’s about to make an exception that underscores his commitment to undermining Obama’s Cuba efforts, however, by lending a hand to a soon-to-be released bill that confronts the administration’s agenda head-on. He’s collaborating with committees of jurisdiction.

In the meantime, the awards for his advocacy of funding for the Florida Everglades — secured through appropriations bills before and after his 2011 appointment — underscore the veteran lawmaker’s thesis that working through spending bills is one of the best ways to get things done.

“Those are the bills that actually pass, one way or the other,” he explained. “It’s much better when you do it through regular order, but one way or other, they have to become law, or the government shuts down.”

He thinks his Cuba riders can withstand the threats of the veto pen.

“Is [Obama] gonna shut down the government in order to directly help the military and intelligence services of the Cuban regime?” Diaz-Balart asked, “Would he shut down the government in order to do business on properties illegally stolen from Americans? That remains to be seen but I think you’ll have a hard time justifying that. And I think that’s why you have to pick your battles.”

New Jersey Republicans Set Stage for Fight on U.S.-Cuba Relations

Diaz-Balart Describes an Immigration Deal Undone

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