By Caren Bohan

WASHINGTON(Reuters) - Elizabeth Warren is folksy
and plain-spoken and favors cardigans over Washington power
suits. Many on Wall Street view her as their worst nightmare
but she is a hero to liberal activists and consumer groups.

This autumn, Warren, a contender to become the top U.S.
consumer financial regulator, could become a focal point in a
political debate over how far government should go to rein in
the financial sector and other corporate interests.

As President Barack Obama wraps up a vacation on Martha's
Vineyard Sunday, a key decision awaits him on the leadership
of the new Consumer Financial Protection Bureau.

White House officials say Warren, a Harvard law professor
and consumer rights advocate, is a strong candidate, although
other people also are under consideration.

The decision may boil down to whether Obama is willing to
take on a fight for her Senate confirmation in the heat of a
battle to help his Democrats avoid losses to Republicans in the
Nov. 2 congressional elections.

Obama aides say there is no decision yet but many analysts
say that from a purely political standpoint, Obama might have
the most to gain by picking Warren.

"She is a symbol for the progressive wing of the party
about the seriousness of the Obama administration's commitment
to consumer protection," said Ross Baker, a Rutgers University
political scientist. "If they put her up and (Senate Republican
leader) Mitch McConnell manages to block the nomination, that's
still good in terms of how the Obama administration stands in
the eyes of the left wing of the Democratic Party."

Former Bush administration official Tony Fratto also
predicted Obama would choose Warren.

Many liberal Democrats, frustrated with what they see as an
overly moderate bent to Obama's economic team, view Warren as
the one and only candidate. "I don't think this White House has
the courage to buck that," Fratto said.

On Wall Street, "there is very strong dislike of her and
what she might do," said Bert Ely, a banking consultant in
Alexandria, Virginia.

Obama also is considering Michael Barr, a Treasury
official, and Eugene Kimmelman, a longtime consumer advocate.

WILL SHE SIT IN THE 'PILOT'S SEAT?'

Baker said that passing over Warren would be like telling
Orville Wright, one of the inventors of the airplane, that he
could not sit in the pilot's seat.

It was Warren who conceived of the idea of the consumer
agency. Its creation was mandated by Congress in the massive
rewrite of U.S. financial regulations enacted in July.

Warren, 61, has spent decades championing the rights of
middle-class families and detailed their struggles in a
best-selling book called "The Two-Income Trap."

She is a janitor's daughter from Oklahoma whose parents
lived through the Dust Bowl and Great Depression. Her father
was a victim of a business partner who took off with money he
had saved to start a car dealership.

"I don't think she's ever looked at folks who are
struggling financially as lab subjects under a microscope.
She's always viewed them as people just like the people she
grew up with," said her daughter, Amelia Warren Tyagi, who
co-authored "The Two-Income Trap" with Warren.

Warren believes the economic system is "rigged more and
more unfairly" against the middle class, Tyagi said, adding
that keeps her mother up at night. "It drives her nuts."

Wall Street fears Warren would use her platform at the
consumer agency to push for policies that would hurt profits on
products like credit cards and stifle their competitiveness.

Warren, who wears her blond hair tucked primly behind her
ears, can disarm critics with her politeness and Midwestern
twang. But she is tough. At 16, she entered college on a debate
scholarship. A bankruptcy expert, she has mastered the arcane
jargon of the financial world.

Raj Date, head of the Cambridge Winter Center financial
research organization, said the "hand-waving and venom" about
her on Wall Street was overblown. He praised her for an ability
to ask the right questions about complex issues.

"She doesn't mind asking questions that other people are
embarrassed to ask and as a result, she quite frequently gets
to the core of substantive issues," Date said.

Warren has a rapport with top White House aides David
Axelrod and Valerie Jarrett. She meets for lunch or dinner
occasionally with senior White House economic adviser Larry
Summers, an ex-president of Harvard who knows her as a
colleague. Over dinner with him in April 2009, she made the
case for the consumer agency and helped get him on board.

Warren has had tense moments with Treasury Secretary
Timothy Geithner in the separate role she has held since late
2008 as head of a panel overseeing the $700 billion financial
bailout. In hearings about the bailout, she has grilled him
about how the money was spent and whether Treasury was doing
enough to spur small-business lending.

But Geithner has lavished praise on her in public recently
and has said she is well-qualified to run the consumer agency.

Senate Banking Chairman Christopher Dodd has said it could
be a tough sell to get Warren confirmed in the Senate where
Republicans might try to block her with a filibuster.

Wall Street's dislike of Warren energizes her supporters.

The National Organization for Women has suggested that if
she is not picked, it will be partly because she is not a
member of the Wall Street "old boys' club." One consumer group,
the Main Street Brigade, has made a rap video about Warren,
lauding her as a sheriff of Wall Street.

If Obama does choose Warren, Republicans would not shrink
from a fight either. Fratto said they would portray her views
on the shape of the financial industry as "radical fringe."

"She's far to the left of the economic team in the Obama
administration," Fratto said. He said Republicans would also
emphasize her academic background and her "complete lack of
experience running a large organization."
(Writing by Caren Bohan; Additional reporting by David
Clarke, Kevin Drawbaugh and Karey Wutkowski; Editing by Eric
Walsh)