The Senate on Monday blocked President Obama's nominee to be ambassador to El Salvador as Republicans opposed the selection over unfounded rumors that her boyfriend of years ago was a Cuban spy and new outrage over a summertime op-ed on gay rights.

Mari Carmen Aponte, a Washington lawyer and Hispanic activist, has served as ambassador in San Salvador since September 2010 after Obama, in response to Republican opposition to her nomination, made her a recess appointee. But her temporary tenure is to run out at the end of the year.

On a vote of 49-37, the Senate refused to move ahead with the nomination despite pleas from Democrats. Senate Majority Leader Harry Reid, D-Nev., left open the possibility of trying to vote again at a later date.

Sen. Bob Menendez, D-N.J., called her an "excellently qualified Latina who is being politically discriminated against."

But her chief foe, Sen. Jim DeMint, R-S.C., said Republicans had pressed for months for details on her background to no avail.

"Why did she refuse to take a lie detector test? Why did she withdraw her nomination under (President Bill) Clinton?" he asked.

The Senate did approve Obama's pick for ambassador to the Czech Republic, Norman Eisen. After voting 70-16 to cut off debate on his nomination, the Senate approved him by voice vote.

Conservative anger toward Aponte is based, in part, on an op-ed she wrote on June 28 in La Prensa Grafica, a daily newspaper in El Salvador. The essay was in response to a State Department cable to ambassadors worldwide urging them to recognize gay pride month.

In a Spanish-language piece titled "For the Elimination of Prejudices Wherever They Exist," Aponte wrote: "No one should be subjected to aggression because of who he is or who he loves. Homophobia and brutal hostility are often based on lack of understanding about what it truly means to be gay or transgender. To avoid negative perceptions, we must work together with education and support for those facing those who promote hatred."

In the op-ed, Aponte noted that the United States and El Salvador were among more than 80 nations that had signed a U.N. declaration for the elimination of violence against gays and lesbians. She also pointed out that El Salvador President Mauricio Funes had signed a decree in May 2010 prohibiting discrimination by the government based on sexual orientation.

But 57 percent of El Salvador's population is Roman Catholic, and several Salvadoran family and religious groups wrote to U.S. lawmakers criticizing Aponte for "abusing her diplomatic status, showing a clear disdain concerning our values and cultural identity." They urged lawmakers to oppose her confirmation and suggested she be removed from the post.

DeMint, writing last month in Human Events, assailed Aponte for the op-ed and revived the old speculation about her personal life.

"Our relationship with the Salvadoran people has been one of trust and friendship for decades," DeMint said. "We should not risk that by appointing an ambassador who shows such a blatant disregard for their culture and refuses to clear unsettled doubts about her previous relationships. It's time to bring Ms. Aponte home."

Thirteen years ago, when Clinton nominated Aponte, reports surfaced that a former live-in boyfriend, Roberto Tamayo, had ties to Cuban intelligence in Fidel Castro's regime and that Cuban intelligence agents had tried to recruit her. The head of the Foreign Relations Committee at the time, Sen. Jesse Helms, R-N.C., signaled he would question Aponte about the allegations at her confirmation hearing; she withdrew her nomination.

In the end, the FBI cleared her. On two occasions, Aponte has received top-secret security clearances.

Menendez said a review of her file showed "nothing to corroborate the vicious allegations on her past." The Cuban-American senator argued that if there were anything in her past that showed ties to Fidel Castro former regime's, he would oppose her nomination.

Menendez pointed out that during her brief tenure she's helped foster a stronger U.S. relationship with the country and El Salvador is the only Latin American country providing troops to fight al-Qaida in Afghanistan.

Sen. Chuck Grassley, R-Iowa, said he had objected to Eisen's nomination because of his handling of the firing of Gerald Walpin, the internal watchdog for the federal AmeriCorps program. Walpin, the national service agency's inspector general, was dismissed over his handling of an investigation of the mayor of Sacramento, Calif., Kevin Johnson, an Obama supporter during the presidential campaign.

The GOP has said Eisen made misrepresentations to Congress about the firing of a federal official.