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 called on Congress to lift the economic and travel embargoes that the U.S. has used for decades in an attempt to force Cuba's leaders toward democracy. Obama has partly eased those restrictions on his own, but continued opposition from many Republicans and some Democrats makes it unlikely that lawmakers will fully revoke those 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 in the White House Rose Garden. ``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.
Other congressional critics included Cuban-American lawmakers like Rep. Ileana Ros-Lehtinen, R-Fla., and Sen. Bob Menendez, D-N.J. He described the thaw as ``incentivizing a police state to uphold a policy of brutality'' to its own citizens.
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 were 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.
Senate Majority Leader Mitch McConnell, R-Ky., issued no new statement on Obama's announcement. In recent months, he has expressed support for critics of the president's effort to improve relations with Cuba.
Strongly negative comments came from contenders for the GOP 2016 presidential nomination. Their 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.
Former Florida Gov. Jeb Bush saw Obama's announcement as ``further legitimizing the brutal Castro regime.'' Sen. Marco Rubio, R-Fla., accused the president of making ``unilateral concessions to this odious regime.''
And Sen. Ted Cruz, R-Texas, accused Obama of ``continuing his policy of unconditional surrender'' to what he called ``one of the most violently anti-American regimes on the planet.''
Rubio and Cruz, both Cuban-Americans, said they would block any effort by Obama to win Senate confirmation of a U.S. ambassador to Cuba, which normally occurs when nations commence full diplomatic relations.
While many congressional Republicans were likely to 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 upgrade the current, lower-level U.S. outpost there ``to embassy status to handle more extensive operations.'' 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.
Since the two countries' surprise revelation last December that they would move toward normal relations, they have taken gradual steps in that direction.
In January, the U.S. lifted some travel curbs on Americans and began permitting U.S. companies to export telephones and computers to Cuba. In May, the administration 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.