Warren: 'I'm out here to speak for middle-class families'

The former White House official who built President Obama's Consumer Financial Protection Bureau from the ground up formally announced her bid for Senate in Massachusetts on Wednesday. 

Warren cited her background growing up in "tough circumstances" and setting up the controversial agency as proof of her ability and will to fight in the Senate campaign.

"I was told when I was down in Washington we couldn't have a Consumer Financial Protection Bureau … and my view on that just meant you stand up and you just push harder, you push back, you don't step down," said Warren.

When asked how she would compete against Sen. Scott Brown (R-Mass.) in a general election, she said, "I can be out-spent, but I can't be out-worked."