Elizabeth Warren for the first time Monday indicated she was considering a Senate bid against freshman lawmaker Scott Brown (R-Mass.) next year in what would become one of the closest-watched races of the 2012 cycle.

If the architect of the Consumer Financial Protection Bureau (CFPB) did decide to take on Brown, it would pit against one another two of the largest personalities to emerge on the Washington scene in recent years.

{mosads}In one corner would be Brown — the pickup-truck-driving Cosmo centerfold who shocked the political world when he won the seat held for decades by the late Sen. Edward Kennedy (D). In the other would be Warren, a liberal rock star, Harvard Law professor, Oklahoma grandmother and Wall Street critic extraordinaire.One indicator of how popular she is: If you typed “Elizabeth” in Google’s search engine Monday, her name came up second — right after actress Elizabeth Taylor.

“It would be a marquee race of 2012, potentially second only to the presidential race,” said Adam Green, co-founder of the Progressive Change Campaign Committee, a liberal group that launched a draft-Warren movement on Monday.

Rumors had swirled for months that Warren was weighing a bid at the urging of Senate Democrats, but she refused to answer questions about the race, while she was still under consideration as head of the CFPB. 

But now that she has been passed over as the first director of the bureau she helped President Obama establish, that speculation is back in full swing.

For the time being, the only thing certain about Warren is that she plans to return to Harvard in the fall. But she gave the clearest indication yet that a Senate run might be in her future.

“I’ve been working 14 hours a day on trying to stand this … agency up, really for more than a year now. … It’s time for a little vacation for me,” she said when asked about a run Monday on MSNBC. “When I go home, I’ll do more thinking then. But I need to do that thinking not from Washington.”

Her comments came shortly after Obama announced the nomination of one of her top deputies, Richard Cordray, to become the CFPB’s first director.

Warren was scheduled to make another appearance on MSNBC late Monday evening — this time on liberal host Rachel Maddow’s show.

Liberal groups pushed hard for the administration to name Warren to the CFPB job but, with that not happening, one group is pivoting its efforts to recruiting her for a Senate run.

The PCCC has gathered more than 350,000 signatures, as well as the support of 89 lawmakers, in the Warren-for-director effort, but is now turning its attention to the Senate race.

“She’s one of the few people who are truly willing to challenge corporate power and stand up on principle for the little guy,” said Green. “Our job is to let her know she will have a grassroots army behind her” if she decides to run.

White House spokesman Jay Carney, when asked Monday if Obama would support Warren if she ran for Senate, declined to comment.

“Let’s see what she decides to do. I don’t have any comment on that,” he said.

Senate Democrats are mum on whether Warren is being recruited as a challenger, although she has spoken to Senate Majority Leader Harry Reid (D-Nev.) and Democratic Senatorial Campaign Committee Chairwoman Patty Murray (Wash.) about it, according to reports.

And Massachusetts Democratic Party Chairman John Walsh told the Boston Globe earlier this month that if the CFPB job fell through, “I would love it if she were interested in joining the [Senate] race. I would talk to her and encourage her in a heartbeat.”

Democrats have long hoped that Warren would run against Brown, seeing Massachusetts as one of their best opportunities to pick off a Senate seat next year. The party is defending 23 seats this cycle to the Republicans’ 10, and the GOP only needs a net gain of four seats (if Obama wins reelection) to take control of the upper chamber.

But Warren would face a formidable foe in Brown, who has banked almost $10 million in his campaign war chest in preparation for a challenger. 

And he would have help from the National Republican Senatorial Committee.

“It’s clear Democrats in Washington are trying to pull the levers here but it’s unclear whether Massachusetts voters believe an Oklahoma native and Harvard professor best represents their views and values.  It’s also clear that Democrats are shaping up to have an even more divisive and late primary on their hands, instead of clearing the field as they predicted they would a few months ago.” – NRSC communication director Brian Walsh said in a statement.Given Massachusetts’ Democratic tilt, Brown, the only Republican in the state’s congressional delegation, is considered vulnerable.

And Warren’s high-profile status would help bring in funds to compete with him.

She hit the national stage first as an overseer of Congress’s bailout watchdog, and then as the leading advocate for a financial bureau devoted to consumers. 

After the CFPB was created as part of the Dodd-Frank financial reform law, she was named a special presidential adviser in charge of setting it up. However, a contentious relationship with congressional Republicans seems to have dissuaded the president from what was believed to be an insurmountable confirmation battle.