President Obama’s planned trip to Cuba next week is being anticipated as an historic chance to thaw relations with Havana in almost every corner of Washington.

Save for Congress.

Publicly, Congress’s biggest Cuba boosters are celebrating Obama’s visit — the first by a sitting president in almost 90 years — as a potential game-changer that could speedily galvanize public support to lift the decades-long travel ban and trade embargo keeping U.S.-Cuba relations partially frozen.

But privately and pragmatically, most lawmakers acknowledge they do not expect 2016 will be the year they help the president knock down the barriers separating the U.S. and Cuba since the Cold War. Until Congress acts, the president can’t fully restore relations between the two countries, cementing that bit of his legacy.

“I think most members of Congress support what the president’s doing, but it’s just unlikely it’ll gel into any formal action,” said Sen. Ben Cardin (D-Md.), the Senate Foreign Relations Committee’s top Democrat, who supports ending the embargo. “For 2016, [Obama] doesn’t have it.”

But Obama isn’t waiting for Congress to move toward restoring economic and diplomatic relations. Last summer, the U.S. and Cuba reopened embassies in each other’s capitals. On Tuesday, Obama announced the Treasury Department would green-light “people to people” trips for anyone wanting to travel to Cuba for educational purposes — effectively opening the door to unrestricted travel – and start permitting Cubans to earn salaries in U.S. dollars.

For now, lawmakers haven’t been able to block Obama’s overtures. Several members, both Republicans and Democrats, will also be joining Obama when he goes to Cuba, a gesture many hope shows that improving relations is becoming a bipartisan issue.

“The broader embargo — there’s some things that make that more difficult, but the travel issue? Just get rid of it,” Sen. Jeff Flake (R-Ariz.), who will be on Obama’s Cuba trip. “If we had that vote on the floor of the Senate tomorrow, we’d get well north of 60 votes.”

But for now, Republican congressional leaders have offered no indication that they’re amenable to adding Cuba legislation to an already packed election-year calendar – much to the frustration of some of their rank-and-file.

“The real issue is that you’re in an election year, so all the air gets sucked out of the room,” said Rep. Tom Emmer (R-Minn.), who introduced legislation to repeal the embargo altogether, and got ten other Republicans to publicly join him. He says there are many more Republicans who support the effort.

Cuba has come up on the campaign trail, and though the presidential candidates are hardly unified on the issue, nearly all of the GOP chatter is critical of the thaw. Sens. Marco Rubio (R-Fla.) and Ted Cruz (R-Texas), both of Cuban-American heritage, are vehemently against lifting the embargo, and though front-runner Donald Trump favors normalizing relations in concept, he said he would have waited for a “better deal.”

Lawmakers have introduced several measures to dilute the embargo and fully restore free travel to Cuba. Last year, some language to improve ties even found its way into a Senate appropriations bill. But it was ultimately left out after clashing with efforts to block Obama’s normalization efforts.

Since then, pro-thaw lawmakers have been trying to revive their efforts. They reconvened a bipartisan working group late last year  — but they’ve only met a couple of times, and are still having trouble agreeing on a strategy.

“I think probably the incremental, piecemeal approach has a better chance of getting support and ultimately affecting our posture with respect to Cuba,” said Rep. Rick Crawford (R-Ark.), who joined the working group to promote agricultural trade with the island nation.

Even if the working group can outline a gameplan in the next few months, there are still some powerful Republicans who want to keep the embargo in place and travel restricted to the island nation. A core group of mainly Republicans and Cuban-Americans remain firmly opposed to normalizing relations, which they see as concessions to a corrupt, dictatorial Cuban regime.

Florida Republicans like Rep. Ileana Ros Lehtinen (R-Fla.) and Rep. Mario Diaz-Balart (R-Fla.) wield considerable influence on the Cuba issue and are a considerable roadblock to congressional action. Lehtinen is a senior member of the House Foreign Affairs Committee and its former chairman, while Diaz-Balart chairs the House Appropriations subcommittee governing transportation.

“I don’t think we can expect great change in the committee process,” said Rep. Jim McGovern (D-Mass.), a long-time advocate for relaxing relations with Cuba, who is also going on the president’s trip. “To the extent that we have some legislative successes, it’s going to be on the floor of the House.”

McGovern said that at a bare minimum, members would try to hold House Speaker Paul Ryan (R-Wisc.) to his claim about wanting an open amendment process in the House, and use that to try to introduce measures to lift at least parts of the Cuban embargo during the appropriations process.

“If we could get a vote on the floor of the House, I think you’re going to see some strong numbers, and strong bipartisan support for these things,” McGovern said. “I think we should pursue everything.”

But with the prospects of floor action slim, supporters are trying to turn their campaign public — and hoping Obama’s trip can serve as a call to arms for constituents and businesses to pressure their lawmakers on the issue.

“If it doesn’t get done, we’ll pick up the pieces and keep moving,” said Rep. Barbara Lee (D-Calif.), who is accompanying Obama to Cuba.

And in the meantime, they want to protect the president’s executive orders from efforts at rolling them back.

“If nothing else happens, I think what has happened so far has been huge,” said Rep. Karen Bass (D-Calif.), who will also be on the Cuba trip.