Elizabeth Warren considers run against Sen. Scott Brown of Massachusetts

Elizabeth Warren, the darling of progressives, on Thursday moved a step closer to running against Sen. Scott Brown by forming an exploratory committee and launching a website for her likely race in Massachusetts.

A consumer advocate and Harvard law professor, she has been signaling for weeks that she is preparing to run against Brown in what will become a closely watched Senate race in 2012.

Amid the frenzy over President Obama’s healthcare overhaul, Brown, with the backing of the “tea party� movement, captured the Senate seat held by the late liberal icon, Sen. Edward M. Kennedy. When Brown won in 2010, he gave the GOP a 41st seat, ending the Democrats’ effective supermajority so that the majority party and its independent allies were no longer able to block a Republican filibuster.

Top Democrats, including Majority Leader Sen. Harry Reid of Nevada, have been urging Warren, now visiting with groups around the state, to run. With Thursday’s actions, she can raise money and solicit volunteers on her website as she decides whether to formally announce her run. About a half-dozen other Democrats are eyeing the race.

EMILY’s List, a group that helps elect to office Democratic women who support abortion rights, gave Warren an immediate boost. In a posting on the group’s website, president Stephanie Schriock praised Warren.

“The EMILY’s List community has been telling me loud and clear that they want Elizabeth Warren in the race to beat Scott Brown,� Schriock wrote. “Today, they got a little bit closer to getting their wish. I’m thrilled that Elizabeth is pursuing this next endeavor with the thoughtfulness and respect that’s been such a hallmark of her career. Starting a listening tour is not only a great way to find out what folks need, it’s a perfect contrast to Republican Scott Brown, who has yet to hold a single public town hall.�

Warren has never run for public office before, but she has been highly visible in consumer circles. President Obama chose her to launch the Consumer Financial Protection Bureau, but strong congressional Republican opposition proved to be too much of a barrier. Obama eventually picked someone else to head the agency.