WASHINGTON - 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 conservative outrage over a summertime op-ed on gay rights.

Mari Carmen Aponte, a Washington lawyer and Hispanic activist, has been ambassador in San Salvador since September 2010 after Obama, in response to GOP opposition to her nomination, made her a recess appointee. Her temporary tenure is to end 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.

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.

A White House statement called the vote "one more example of the type of political posturing and partisanship the American people are tired of seeing."

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