Senator Elizabeth Warren of Massachusetts brought her ascendant presidential campaign to New York City on Monday night, unspooling a forceful argument for attacking corruption in government in a defining speech of her White House bid.

Addressing thousands of supporters in Washington Square Park, some holding up “I’m a Warren Democrat” signs, Ms. Warren pressed her case to bring sweeping change to an economic and political system she views as fundamentally tilted to favor the wealthy and powerful.

She spoke near the site of the Triangle shirtwaist factory fire of 1911, which killed 146 garment workers, most of them women. The fire spurred a push to improve workplace safety, which Ms. Warren harnessed as a parallel for the far-reaching change she wants to pursue as president.

And once again, she urged Democrats to embrace her call for dramatic change — not the kind of incremental approach favored most notably by Joseph R. Biden Jr., the former vice president and the primary race’s front-runner.