Democrats looking to curry favor with Hispanic voters ahead of the 2012 elections have scheduled a test vote in the Senate today on the nomination of Mari Carmen Aponte to be the ambassador to El Salvador.

But Aponte may fall victim to what would be the third GOP-led filibuster of a nomination in a week, because Democrats may not be able to rally the 60 votes needed to cut off debate on her nomination. Last week, Republicans blocked both a judicial nominee and the president’s pick for the Consumer Financial Protection Bureau.

Opposition to Aponte’s nomination has come from Sen. Jim DeMint (R-S.C.), who has concerns over an op-ed she wrote in an El Salvadoran publication that he believes promotes homosexuality. He also raised concerns about her relationship with a man alleged to be a Cuban spy.

Sen. Marco Rubio (R-Fla.) also opposes the nomination — and those of Roberta Jacobson to be assistant secretary of State for Western Hemisphere affairs and Adam Namm to be ambassador to the Republic of Ecuador — over a disagreement with the Obama administration’s policies regarding Cuba and Nicaragua.

Aponte is already serving as the ambassador after receiving a recess appointment last year. But that appointment expires at the end of the year unless the Senate confirms her nomination.

“If Republicans oppose this nomination en masse, it will send the wrong signal to a very large community that they cannot afford to offend,” a Senate Democratic leadership aide said Friday.

In the absence of any real legislative progress on matters important to Hispanic voters, the Aponte nomination appears to allow Democrats to cast themselves as concerned about Latino-centric issues.        

Democrats, who control the Senate in a divided Congress, have struggled to pass legislation important to Hispanic voters.

While a push for immigration reform could still be in the offing for next year, last December the Senate narrowly failed to pass the DREAM Act. The measure would provide a path to citizenship for some undocumented immigrants who agree to go to college or join the military.

The bill was approved in the House last year, when Democrats held the majority, but its prospects for passage have plummeted when Republicans, who want to focus on border security, took over following the 2010 elections.

The Aponte nomination is strongly supported by the Congressional Hispanic Caucus, and two of its leaders — Chairman Charlie Gonzalez (D-Texas) and First Vice Chairman Rubén Hinojosa (D-Texas) — sent a letter Tuesday to Senate Minority Leader Mitch McConnell (R-Ky.) urging him to support Aponte’s nomination.

“Since her recess appointment in August 2010, Ms. Aponte has served our country with distinction and is deserving of confirmation,” the letter said. “Her extensive experience in the government, non-profit and private sector have helped forge relationships with Salvadoran leaders of all political allegiances.”

Before assuming the position of U.S. ambassador to El Salvador, Aponte worked as an attorney and consultant with Aponte Consulting and served on the board of directors of Oriental Financial Group Inc. From 2001 to 2004, Aponte was the executive director of the Puerto Rico Federal Affairs Administration.

Before that, she practiced law in Washington, D.C., for nearly 20 years, and she has served as a member of the board of directors of the National Council of La Raza, the Puerto Rican Legal Defense and Education Fund and the University of the District of Columbia.

At a news conference Tuesday, several Congressional Hispanic Caucus members and Sen. Bob Menendez (D-N.J.) sought to make the case for her nomination.

“Our diplomacy should know no delay,” Rep. Xavier Becerra (D-Calif.) said, later adding, “It would be an immeasurable mistake to play politics with her appointment and put on hold our relations with El Salvador.”

Menendez said, “This is Republican obstructionist politics at its worst, and I am shocked that they place more value on bringing down an administration nominee than they do on having a superior ambassador in San Salvador to promote and guard American bilateral, commercial and security interests.”

DeMint laid out his opposition in an article he wrote last month in Human Events. In the item, he stressed that the op-ed Aponte wrote in El Diario de Hoy is pro-homosexual and anti-family. Her article discussed homophobia and said that everyone has a responsibility to “inform our neighbors and friends about what it means to be lesbian, gay, bisexual or transgender.”

DeMint added that there is a coalition of conservative groups in El Salvador that also opposes Aponte over the op-ed. 

“The coalition, which includes dozens of organizations from El Salvador and other countries like Mexico and Honduras, said the only thing that they agreed with Ms. Aponte about is that violence against homosexuals should be repudiated,” DeMint said.

Regarding her relationship with a man targeted as part of an FBI counterintelligence investigation and who allegedly worked for Cuba’s spy agency, DeMint said, “The White House has continually denied requests for information regarding her past ties to Cuban intelligence officials, and her misguided editorial doesn’t inspire confidence either.”

Rubio said his opposition has nothing to do with her personally but with his opposition to the administration’s foreign policy in the Western Hemisphere.

“Rather than stand up to tyrants and promote democracy, this administration’s policy towards Latin America has been defined by appeasement, weakness and the alienation of our allies,” Rubio said. “Earlier this year, I encouraged the administration to seize these nominations as an opportunity to outline a plan to steer U.S. policy in the Western Hemisphere towards renewing America’s commitment to promoting democracy and free markets.”

Heritage Action for America also opposes the Aponte nomination and will key-vote her nomination.

“Any nominee who has relationships that potentially threaten our national security and pushes an agenda counter to the culture of the nation she is supposed to work with has no place as a U.S. Ambassador, especially to a country as strategically important as El Salvador,” the group said in a statement.