(CNN) -- Senate Republicans on Monday blocked President Obama's choice to be ambassador to El Salvador after raising questions about whether her former boyfriend was a spy for Cuba. Republicans also were concerned that Mari Carmen Aponte wrote a commentary about gay pride that offended some citizens in the conservative Catholic country.
Aponte is serving in the post temporarily as a recess appointment that expires at the end of the year. Efforts by the White House and congressional Democrats to defend and promote Aponte to a permanent position fell short when the Senate voted along party lines against her.
The vote was 49 to 37. Sixty votes were needed to move the nomination forward.
The White House said with the vote, Senate Republicans chose "to play politics with America's national interests" and that Aponte had served the nation well.
"Today's filibuster is one more example of the type of political posturing and partisanship the American people are tired of seeing in Washington. Now is not the time for playing politics, it's time for Congress to do the right thing for the American people."
Sen. Jim DeMint, R-South Carolina, one of the Senate's most conservative members, led the effort to defeat Aponte. He said questions linger about Aponte's relationship with the Cuban that were first raised in her failed effort to become ambassador to the Dominican Republic in 1998.
"Primarily, the questions centered around the 12-year romantic relationship she had with a man who was targeted as part of an FBI counterintelligence investigation and allegedly worked for Cuba's spy agency," DeMint said on the Senate floor. "A high-ranking Cuban defector claimed that Cuban intelligence tried to recruit Ms. Aponte to be a spy for the Cuban government."
DeMint complained Republican senators were never given full access to FBI files and other documents that could have alleviated their concerns.
Democrats complained of "unjustified resistance," by Republicans to Aponte's nomination, in the words of Sen. Dick Durbin of Illinois.
"The FBI looked into the matter. They investigated it. Aponte cooperated completely and she also severed all her ties with this individual," Durbin said on the Senate floor. "She was never the subject of any FBI investigation or ever accused of any wrongdoing."
DeMint also complained about a June op-ed Aponte wrote in a Salvadoran newspaper concerning gay rights that he said was "hostile to the culture of El Salvadorans" and "present(ed) even more doubts about her fitness for the job."
Again, Durbin defended Aponte and said the article was written at the direction of the State Department in honor of Lesbian, Gay, Bisexual and Transgender Pride Month.
"The article was entitled, 'For the Elimination of Prejudices Wherever they Exist.' Her op-ed disavowed violence and hatred against individuals based on their sexual orientation, urging education and understanding," Durbin said. "Those are hardly radical ideas. Most members of the Senate, at least let's say many members of the Senate, have given speeches along these lines."