The historic plan announced by President Obama on Wednesday to normalize relations with Cuba was met with heavy bipartisan resistance on Capitol Hill, raising questions of whether Congress will even consider easing a more than 50-year trade embargo against the communist state -- let alone end it.
Obama said the United States will cease what he called an “outdated approach” with Cuba, and take steps to normalize diplomatic relations -- including opening an embassy in Havana -- after American Alan Gross was released from the country following five years in prison as part of an agreement that also included the release of three Cubans jailed in the U.S.
Obama also called on Congress to have an "honest and serious debate" about lifting the trade embargo, which has been in place since 1962.
But Republicans, and even some Democrats, pushed back strongly, with some GOP heavy hitters calling Obama's plan “another concession to tyranny.”
“These changes will lead to legitimacy for a government that shamelessly continuously abuses human rights but it will not lead to assistance for those whose rights are being abused,” Sen. Marco Rubio, R-Fla., said Wednesday.
"It's absurd and it's part of a long record of coddling dictators and tyrants," Rubio told Fox News, claiming the administration is "constantly giving away unilateral concessions ... in exchange for nothing." Rubio called Obama the "worst negotiator" the U.S. has had as president "since at least Jimmy Carter." He also said Congress would not support lifting the embargo.
Incoming Senate Majority Leader Mitch McConnell also criticized the administration’s plan to change the current U.S. relationship with Cuba. McConnell said he defers to Rubio on the matter.
Sen. Bob Menendez, D-N.J., who, like Rubio, is a Cuban-American lawmaker, said this is a moment of "profound relief" for Gross and his family. But he voiced concerns that this constituted a "swap of convicted spies for an innocent American."
"President Obama's actions have vindicated the brutal behavior of the Cuban government," he said in a statement. "Trading Mr. Gross for three convicted criminals sets an extremely dangerous precedent. It invites dictatorial and rogue regimes to use Americans serving overseas as bargaining chips."
Sens. Lindsey Graham, R-S.C., and John McCain, R-Ariz., said in a joint statement that the move damages American values.
"Unfortunately, we fear the most damaging chapter to America’s national security is still being written. We dread the day President Obama takes to the podium to announce a nuclear deal with the Iranian ayatollahs which does little, if anything, to deter their nuclear ambitions, placing our nation and our closest allies in even deeper peril,” the said in a joint written statement.
Other U.S. lawmakers hailed the agreement, and some even joined Gross on the plane ride to the U.S. -- Rep. Chris Van Hollen, D-Md.; Sen. Patrick Leahy, D-Vt.; and Sen. Jeff Flake, R-Ariz., were on that flight.
U.S. officials said Pope Francis was personally engaged in the process as well and sent separate letters to Obama and Castro this summer urging them to restart relations.
Senior administration officials said Obama spoke with Cuban leader Raul Castro for more than 45 minutes on Tuesday, the first substantive presidential-level discussion between the U.S. and Cuba since 1961.
Obama also plans to take several executive actions, including expanding travel and economic ties to the island. According to a White House document, the U.S. government would raise remittance levels and authorize certain travel to Cuba, as well as start a review of Cuba's designation as a state sponsor of terrorism.
Obama also has formally directed the State Department to launch talks with Cuba to re-establish diplomatic relations, which were cut in 1961. The embassy in Havana would be opened "in the coming months," according to the White House.
Officials said the Cuban government was releasing 53 political prisoners. The announcement comes after Gross was freed, as part of an agreement that included the release of three Cubans jailed in the U.S.
Gross landed in the U.S. shortly before noon on Wednesday.
A senior Obama administration official told Fox News that Gross left Cuba on a U.S. government plane Wednesday morning, and was "released on humanitarian grounds by the Cuban government at the request of the United States."
The three Cubans released are part of the so-called Cuban Five -- a group of men who were part of the "Wasp Network" sent by Cuba's then-President Fidel Castro to spy in South Florida. The men, who are hailed as heroes in Cuba, were convicted in 2001 in Miami on charges including conspiracy and failure to register as foreign agents in the U.S.
Two of the Cuban Five were previously released after finishing their sentences.
Cuba was also releasing a non-American intelligence "asset" along with Gross, according to a U.S. official. Administration officials claimed that Gross was not technically traded for the three Cubans, and that his release was humanitarian.
Obama administration officials had considered Gross' imprisonment an impediment to improving relations with Cuba, and the surprise deal was quickly making way for rapid changes in U.S. policy.
The president has taken some steps to ease U.S. restrictions on Cuba after Raul Castro took over as president in 2010 from his ailing brother. He has sought to ease travel and financial restrictions on Americans with family in Cuba, but had resisted calls to drop the embargo. Obama raised eyebrows when he shook hands with Raul Castro at Nelson Mandela's memorial service last year.
Gross was detained in December 2009 while working to set up Internet access as a subcontractor for the U.S. government's U.S. Agency for International Development, which does work promoting democracy in the communist country. It was his fifth trip to Cuba to work with Jewish communities on setting up Internet access that bypassed local censorship.
Fox News' Jake Gibson, Wes Barrett and The Associated Press contributed to this report.