Loud but hardly universal catcalls from Republicans underscored the obstacles and opportunities ahead as U.S. and Cuban leaders announced an opening of embassies in Havana and Washington and a resumption of diplomatic relations severed the year President Barack Obama was born.

Obama also asked Congress to lift the economic and travel embargoes that the U.S. has used for decades to try forcing Cuba’s leaders toward democracy. Obama has partly eased those restrictions on his own, but opposition from many Republicans and some Democrats makes it unlikely that lawmakers will fully revoke the bans quickly.

Labeling the moment “a choice between the future and the past,” Obama on Wednesday revealed the latest steps in a half-year of rapid-fire improvements in relations between two nations that lie 90 miles apart but have spent nearly six decades separated by light years diplomatically and economically.

“There are those who want to turn back the clock and double down on a policy of isolation,” Obama said. “But it’s long past time for us to realize that this approach doesn’t work.”

In an exchange of notes with Cuban President Raul Castro, the two governments said that on July 20, they will open embassies in each other’s capitals that have been shuttered since 1961. That is when President Dwight Eisenhower broke relations with the communist regime of Raul’s brother, Fidel Castro, setting the tone for decades of Cold War hostility that included failed U.S.-backed efforts to overthrow the island nation’s leaders.

Many Republicans said Obama had made the wrong move.

“Relations with the Castro regime should not be revisited, let alone normalized, until Cubans enjoy freedom,” said House Speaker John Boehner, R-Ohio.

Denunciations also have come from several 2016 GOP presidential hopefuls, including former Florida Gov. Jeb Bush and Cuban-American Republican Sens. Marco Rubio of Florida and Ted Cruz of Texas. In a typical comment, Bush said warming relations should “advance the cause of human rights and freedom for the Cuban people” and said the administration’s moves were “failing this test.”

In the short-term, congressional battles seem likely on two fronts: administration efforts to appoint an ambassador to Cuba and to win extra funds to upgrade its existing diplomatic facilities there to an embassy.

Rubio and Cruz each said they would try blocking any Obama effort to win Senate confirmation of an ambassador to Havana. A confirmation vote will not occur unless it is scheduled by Senate Majority Leader Mitch McConnell, R-Ky., who in recent months has criticized a harmonizing of relations with Cuba.

While Republicans are likely to strongly oppose large expenditures to improve relations with Cuba, the administration may be able to use smaller amounts to buttress its diplomatic presence there.

Obama has requested $6 million to improve the current, lower-level U.S. outpost there. Congressional aides said that even without specific approval from lawmakers, the State Department could well access that money because agencies can unilaterally shift relatively small amounts among their budget accounts.

Though it’s not yet law, the GOP-led House Appropriations Committee approved foreign aid legislation last month barring work on a U.S. Embassy in Cuba unless Obama certifies that Havana is meeting the terms of a 1996 statute aimed at fostering democracy in Cuba. That includes extraditing people wanted in the U.S. for crimes.

The Republican-controlled Senate Appropriations Committee plans to write its version of the aid measure next week.

The GOP presidential contest is dominated by conservative voters and promises a strong turnout from anti-Castro Cuban-Americans living in the pivotal state of Florida. The strong opposition from those who could lead the GOP in next year’s presidential and congressional elections makes it harder for many Republicans to embrace Obama’s actions.

But at a time when the U.S. Chamber of Commerce, agriculture groups and other business organizations have backed moves toward liberalizing trade with Cuba, some Republicans have been more positive.

Sen. Dean Heller, R-Nev., cited “numerous opportunities mutually beneficial to the people of both countries,” while Sen. Jeff Flake, R-Ariz., said it was time to abandon “five decades of failure.”

Gradually growing GOP support strengthens Obama’s hand to continue removing barriers with Cuba on his own, “even if Congress doesn’t do the heavy lifting,” said Julia Sweig, a Cuba specialist and senior research fellow at the University of Texas in Austin.

The two countries’ surprise revelation last December that they would move toward normal relations has been followed by other steps. The U.S. has lifted some travel curbs on Americans and began permitting U.S. companies to export telephones and computers to Cuba, and has removed Cuba from the list of countries sponsoring terrorism.

Yet divisions remain.

The U.S. remains focused on Cuba’s reputed human rights violations. Cuba wants an end to the U.S. economic embargo, the return of the U.S. military base at Guantanamo Bay and a halt to U.S. broadcasts aimed at the island.

(AP)