Cecilia Muñoz, who in her pre-White House life was one of the most vocal and visible advocates for immigration reform, suddenly reappeared last week after months in relative obscurity.

The reason?

To make an appeal for her lifetime cause -- overhauling the country's anachronistic immigration system. In the process, the highest-ranking Hispanic in the Obama administration seems to have taken the role of the face of the White House on this controversial issue.

Muñoz, 50, President Obama’s chief domestic policy advisor, sent a mass email request last week -- from official White House address -- for personal stories to bolster support for pending immigration legislation.

It is a critical moment for immigration reform, which would include both tighter enforcement and the more controversial path to legal status for millions of undocumented immigrants.

Where previous efforts to reform immigration have fallen apart, this time bipartisan bills in Congress seem to have the best shot at passing, thanks in large part to the heavy Latino turnout for the 2012 presidential election.

Muñoz spent many years as top lobbyist at the National Council of La Raza, one of the leading national Latino advocacy groups, fighting for undocumented immigrants to be able to adjust their status.

“This is the start of a national debate,” Muñoz said in her email appeal for personal stories. “Across the country, we're having a serious discussion about how we can build a fair and effective immigration system that lives up to our heritage as a nation of laws and a nation of immigrants.”

The White House has not yet responded to a request by Fox News Latino to interview Muñoz.

“We need your help to make sure that genuine, personal perspectives are part of the conversation,” Muñoz said in her email. “When Americans from all over the country -- each with different backgrounds, each from different circumstances -- all speak out with the same voice, it's powerful in a way that's hard to ignore. We've seen it again and again, in debate after debate.”

Then she turned the message into a direct appeal to the American public to get involved.

“This is the kind of issue where putting a face on the push for reform takes an abstract concept and makes it real. So share your American stories with us, and we'll put them to use,” Muñoz wrote.

Advocates for more liberal immigration policies say it’s clear that Obama is enlisting heavy artillery to improve the odds of a reform bill passing.

“It's a sign that immigration reform is a top priority of the White House,” said Frank Sharry, the founder and executive director of America’s Voice, which favors more lenient immigration reform. “She's the quarterback and she's making plays.”

Muñoz’s reappearance as a leading the charge on immigration for the White House, highlighted in a recent New York Times profile, has also attracted the attention of her long-time critics.

The Center for Immigration Studies, a think tank that calls for reduction in illegal and legal immigration, also took notice of Muñoz’s revived leading advocacy role.

The center said that in her past role as an immigration lobbyist, Muñoz wrote negatively about workplace immigration enforcement and conceded that efforts to legalize undocumented immigrants had not succeeded in cracking down on the problem of unlawful status.

“If Muñoz’s past is any guide, it is likely that the [Senate] bill’s workplace enforcement provisions would be put on the back burner the moment it is signed into law,” CIR said in a statement.

Muñoz has been under fire before, by Latinos and immigrant advocacy groups themselves, particularly when the White House sent her to defend Obama’s controversial record-breaking number of deportations.

Some called her a “vendida,” or “turncoat,” for defending a highly controversial enforcement approach and moving farther away from her days as one of the nation’s most high-profile and respected immigration advocates.

She defended the enforcement, saying it was Congress setting policies.

“Congress allocates the resources for deportation,” she told Fox News Latino in an interview last year, “and the Executive Office has to spend it.”

She argued that immigration enforcement is now better focused, more on criminals and moving away from low-priority cases such as undocumented immigrants who were brought as minors, and who last year were given a reprieve from deportation under a new policy by Obama called “deferred action.”

In the interview, she defended Secure Communities, a controversial program through which local law enforcement officials cross-check information about people they’ve arrested and detained against a federal database.

Critics of Secure Communities, and many other enforcement programs, complain that they often cast too wide a web that catches and deports non-criminals who are here on immigration violations.

Her defenders said that she has been working behind the scenes to push for immigration reform.

“The President has been experiencing some major reversals of political fortune lately, especially his defeat on the gun violence issue, so that immigration reform has gained in importance for him politically,” Angelo Falcon, director of the National Institute for Latino Policy, told Fox News Latino.

 “However, it has also been made known that his direct involvement in it advocacy would be counterproductive with the House and that he should promote Congressional leadership on this as he did with Obamacare,” Falcon said.

“His use of Cecilia as his surrogate on this issue reflects its increased importance and his need to downplay his personal role as an polarizing advocate,” Falcon added. “At the same time, he will be making some major compromises on the immigration reform bill that many Latino and other immigrant advocates will be unhappy with and Cecilia is the person he has with the most credibility on this issue.”

Elizabeth Llorente can be reached at elizabeth.llorente@foxnewslatino.com

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