Neera Tanden is assuming the leadership of the Center for American Progress at a key time as the country prepares for the 2012 presidential election. (Marvin Joseph/The Washington Post)

Neera Tanden had just started cutting down her conservative co-panelist at a health-care symposium last week when the moderator stopped her short.

“Neera, let me introduce you properly,” he interrupted. “Because Neera is a big deal.”

On Nov. 1, Tanden assumed the presidency of the Center for American Progress, Washington’s leading liberal think tank, which is an incessant advocate for a broad progressive agenda and as such a sharp thorn in President Obama’s left side. Her predecessor, the uber-connected John Podesta, is a tough act to follow, but Tanden, a veteran of the Clinton administration, Hillary Rodham Clinton’s campaigns and Obama’s policy bench, does not lack self-confidence.

At 5 feet 2 inches tall, with an infectious laugh and impatience for ineptitude, Tanden brims with a moxie that can shift to sarcasm. Critics and allies alike describe her as an effective molder and messenger of intricate policy, as well as an expert practitioner of in-house politics. Friends say she is remarkably well-rounded: a model wife and mother, ideal company for a glass of wine, a perfect partner for spontaneous office dancing.

Now, after two decades of making her bosses look smarter from behind the scenes, the 41-year-old Indian American is out front on her own. To preserve the cachet of her think tank’s top job, which Podesta established as one of the most influential perches in the city, Tanden has the tricky task of convincing a self-reliant president that the path toward economic recovery, reelection and a bold progressive future runs through her shop.

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The danger of the road already taken, she argued, is painfully clear.

“The administration created a series of expectations that created a political problem for the president,” said Tanden, referring to the administration’s emphasis on negotiations with Republicans insistent on cutting spending. Now, Tanden argued, “the president is no longer like ‘I’m sort of like these guys,’ ” she said, referring to Republicans. As a result, the 2012 election “will be a stark choice.”

Podesta, who stepped aside to pursue projects including helping out Secretary of State Clinton, noted that the president’s new confrontational posture reflects the advice of CAP, and that his jobs bill bears a lot of CAP ideas. Obama’s sudden preference for executive orders is also out of its playbook. Podesta credited Tanden with helping to lead an effort to determine “the structure of the jobs program” and how the administration “would approach the long-term fiscal challenges.”

Perhaps as a result, or out of deference to Tanden’s new title, she received personal congratulations Friday from Presidents Obama and Bill Clinton as she shuttled from a CAP event to a Georgetown panel discussion to a White House celebration toting a short stack of papers. A host of D.C. power brokers called her a “big shot,” gave her “props,” and sent her flowers.

Josh Gotbaum, the government’s chief pension manager, wished her “whatever the Indian version of mazel tov is.” Tanden replied, laughing, that Jews and Indians had a lot in common: “Our mothers want us all to be doctors.”

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Tanden and her backers like to frame her job as reflecting a generational change, a shift from white male management to a younger face with color. She peppers her high-speed commentary with second-generation references, including how, because of the “Indian thing” she named her 9-year-old daughter Ilina, a Sanskrit word meaning “possessing high intelligence,” and nearly called her 6-year-old son Jadvana, meaning ‘victory and strength,” before settling on Jaden. (“A name that ends in a vowel is not a gift you want to give your son in America,” she said.)

And Tanden, who is highly protective of her own image, knows what sells in America and in American politics. Like, say, a compelling Horatio Alger tale.

She tells of how, when she was 5, her father left her and her mother and brother in Bedford, Mass., to return to India, selling the family’s house and taking the profits with him. (“I’m not going to talk about him,” Tanden said. “I’m not Lindsay Lohan.”) Welfare checks softened the fall for Tanden’s now single mother, and a low-income housing program in a middle-class community provided them with a home.

“This,” she said, “is why I’m a progressive.”

Her mother eventually found work and set a high academic bar: When a teacher deemed her first-grade schoolwork satisfactory, Tanden’s mother bluntly told her daughter that wouldn’t do. Tanden became a high-school debater, a “nerdy girl” with a dream of practicing civil rights law. She took that goal to UCLA, but said it was dashed by the 1990 retirement of liberal lion Justice William Brennan from the Supreme Court. Tanden’s logic, as she explained through tears at the time to her future husband, artist Benjamin Edwards, was that a conservative-tilting court would never side with her arguments. Implicit in the thinking was that Tanden envisioned herself arguing before the Supreme Court.

Instead, she threw herself into politics. With the help of campaign posters designed by Edwards, whom she had met while volunteering for Michael Dukakis, Tanden was elected vice president of the UCLA student body on a slate of students of color. She volunteered for Bill Clinton’s campaign and ultimately introduced him at the last event of the Democratic primary in June 1992.

After graduating from Yale Law School and landing some key internships, Tanden worked her way up during the second Clinton term to become the senior domestic policy adviser for the first lady.

“When I first started working with her, she was so demure,” said Patti Solis Doyle, one of Hillary’s closest advisers at the time, who later discovered that Tanden “was just trying to make a good first impression. It didn’t take long for her to show how strong and smart and loud she was.”

Tanden became so close to the first lady that Clinton threw her a wedding party in East Wing’s Yellow Oval Room in 1999. At the event, Clinton asked Tanden’s mother if she was proud of her daughter’s accomplishments. “A lot of her friends are partners at law firms and make a lot more money,” Tanden recalled her mother saying, as she stood by mortified. For months afterward, Clinton asked if she was financially okay.

A week after the party, Tanden joined Clinton’s campaign for Senate in New York as issues director and produced a barrage of policy proposals for the campaign. She spent the days gobbling Pirate’s Booty and blew off steam in the office by dancing to Macy Gray and Moby.

Seven years later, after the senator pushed for her involvement in the founding of CAP in 2003, Tanden joined another Clinton campaign — for the presidency.

“Not as much dancing,” Howard Wolfson, Clinton’s communications director and one of Tanden’s best friends, said to describe the change in atmosphere from the previous campaign.

As Clinton fell behind to Obama, fractures emerged in the campaign. Tanden proved a razor-elbowed partisan against chief strategist Mark Penn and others. The campaign’s wreckage was strewn with casualties, but Tanden went on to work for Obama in the general election. The administration then hired her as a key aide on the president’s health-care reform team. Frustrated by the administration’s insular culture, she returned to CAP in February 2010, with the tacit understanding that she would soon get the top job, according to people with knowledge of the deliberations.

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“Here’s where we’re going,” Tanden, wearing a gray skirt suit accented with a purple scarf, said as she stood at the top of an elevator leading to the Grand Hyatt’s basement. She pointed to a sign that read “National Congress on Healthcare Clinical Innovations, Quality Improvement and Cost Containment.” Asked if she looked forward to a life of policy panel discussions in hotel ballrooms, she said, “If you keep it to a minimum, you throw up less.”

As the head of CAP, she will become a more visible face on television, in the White House and on the fundraising circuit. She will oversee a $40 million budget and 250 employees spread over four floors of a building on H Street NW. Strategically, Tanden said her goal, beyond getting the president reelected, is to have bold policy proposals in place for the beginning of the next term, when she predicts Republicans will be stunned into submission. One shift she envisions is for the government to identify sectors of potential growth for investment, from nanotechnology to climate change mitigation, to better compete in a world in which the United States needs to pick its spots. She said she will have the “final call” on her organization’s way, and tacitly, she hopes, the White House’s.

Tanden spent the health-care panel taking notes and then jabbing an opponent from the American Enterprise Institute with sugarcoated barbs. As a woman, she observed in a cab after the panel, “you can’t come down like a hammer. If you are particularly aggressive, it’s viewed differently. I definitely learned that lesson from Hillary Clinton.”

At the end of the day, Tanden waited with costumed kids in line at the South Gate of the White House for a celebration honoring the Hindu holiday of Diwali. Two years ago, the White House left Tanden off a guest list for a state dinner with India. The oversight is not likely to be repeated.

“My friend, Neera Tanden,” Obama announced to the crowd at the Diwali event, as Tanden stood in recognition. “The new president of the Center for American Progress.”