Wall Street put its money on a Romney victory but, alas, was sorely disappointed. Looking at the manner in which big bank stocks dropped post-election, it seems like investors felt the same way.

Oh, well. Now, dreams of repealed regulatory restrictions on profits are just that, and big banks must learn to make nice with a president who, without the burden of another White House run on his mind, might be less inclined to compromise on issues affecting "fat cats."

But, the election also saw Massachusetts' Elizabeth Warren ascend to the late Sen. Edward Kennedy's former office -- most recently occupied by Scott Brown. With her unabashed attachment to liberal values and lack of sympathy for Wall Street, I would suggest that she will be more of a threat to the biggest banks than even Obama.

A defender of the average consumer
Many know Warren as the driving force behind the Consumer Financial Protection Bureau, which banks dislike intensely and had hoped to undermine if Romney won the White House.

Indeed, as an article in Forbes notes, she and the CFPB were instrumental in getting foreclosure fraud suspects JPMorgan Chase (NYSE:JPM), Bank of America (NYSE:BAC), Citigroup (NYSE:C), Wells Fargo (NYSE:WFC) and Ally Financial to cough up $20 billion more than they bargained for in a settlement earlier this year. Except for Ally, all of the other banks were in the top 20 list of campaign donors for the Romney campaign.

Then, again, her activism on behalf of taxpayers as Chair of the Troubled Asset Relief Program probably didn't garner her any points with the big guys, either.

With this bit of tension already in the air, Warren began trumpeting -- even before the election -- her desire to see Glass-Steagall reinstated in law if current regulations can't rein in the big banks. Not only does she think breaking up the big banks is a good idea, but she has also called on Jamie Dimon, the charismatic CEO of JPMorgan, to resign his seat at the Federal Reserve Bank of New York.

Is she powerful enough to pull it off?
Warren is a strong personality, and many feel that her well-known consumer-defense, anti-TBTF bank background is responsible for her victory over Brown. Conservatives don't like her, but she may very well be able to rally the troops for more bank-bashing once she gets her land legs in Washington.

There's no doubt in my mind that a woman who has been put in charge of two such important financial commissions will not be ignored, even if what she has to say doesn't please Wall Street. Combined with an Obama win, the whole discussion on breaking up and reining in the banks will surely be on tap very soon. It's enough to make big banks wish they'd sent their money to the other camp.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.