Vanessa Selbst spent part of her opening day at the World Series of Poker’s main event fighting for social justice which, along with an aggressive playing style, has come to define her career.

“First break: constant flow of men in women’s bathroom, and they don’t even have the decency to close the stall doors,” Selbst said two days ago on Twitter, prompting the Las Vegas tournament’s organizers to quickly add security.

Selbst, who turns 30 tomorrow, honed her poker skills while attending Yale University, eventually playing full time after graduating in 2005 with a political science degree. Worried about wasting her potential, she returned to the New Haven, Connecticut, school and earned a law degree in 2012.

Since then she’s focused some of her time on a foundation to fund projects that challenge social inequality. She’s also returned to poker, becoming the most successful female in history with more than $10.5 million in documented tournament earnings.

“I tried to not be a poker player,” Selbst said in a telephone interview from Las Vegas, where last month she tied Barbara Enright as the only women to win three World Series championship bracelets. “I thought that I was just going to be a lawyer and then I went on to win a couple of tournaments and figured maybe I can make this work.”

Top Rank

She has. Selbst spent four weeks atop the Global Poker Index, a ranking of the game’s top players, before falling to No. 2 behind Germany’s Ole Schemion. She was the first woman to head the list, while the next highest-ranked female is Samantha Cohen, who is 103rd.

Today, Selbst begins the second day of the WSOP’s $10,000 buy-in No-Limit Hold’em World Championship, otherwise known as the Main Event, which pays the winner $10 million. Selbst started with 30,000 in chips, fell to about 3,000 and finished July 7 at 38,000.

Selbst’s success is due to an aggression that “constantly puts you in a difficult position,” according to Norman Chad, an ESPN poker analyst.

“Nobody wants to see Vanessa at their table,” Chad said in an e-mail. “It’s as if her cards don’t matter; she forces her opponent to make tough decisions for big chunks of their chips. And you never know what she has.”

Selbst lived in Brooklyn, New York, before moving to Montclair, New Jersey, when she was 10. She began playing poker with friends in high school after seeing the Matt Damon movie “Rounders.”

College Poker

After following in the footsteps of her mother, Ronnie, by attending Massachusetts Institute of Technology for a year, Selbst transferred to Yale, where she played poker in home games and on the Internet, and spent her free time discussing strategy on online forums.

Out of boredom, Selbst said she ended up playing about 40 percent of poker hands when the norm was to play about 20 percent. The decision helped her learn how to maneuver out of tricky situations by knowing how to exert more pressure than her opponents could stand.

“When you’re playing really bad cards, your own cards don’t matter,” she said.

It’s a style that many young players used in 2010-11, though few still do, said Daniel Negreanu, the defending WSOP Player of the Year and poker’s all-time money leader, according to the Hendon Mob database.

“They’ve gone back to being a little more careful,” Negreanu said in a telephone interview. “It’s just her that’s stayed aggressive.”

Foolish Move

The style made Selbst look foolish during her national television debut on ESPN at the 2006 WSOP, where an ill-timed bluff wiped out her stack of chips at the final table of a $2,000 no-limit event.

“I’m sure I made fun of her; that’s probably the last time I criticized her play,” said ESPN’s Chad. “How can I evaluate or criticize her? She plays at another level -- I can’t even understand what she’s doing most of the time.”

Selbst’s latest World Series bracelet, along with an $871,148 payday, came in a $25,000 buy-in No Limit Hold ’em event in May.

In addition to poker, Selbst plans to use her Yale Law background to challenge social injustice. A new Urban Justice Center board member, Selbst in 2010 founded Venture Justice, a non-profit that provides seed money for projects to fight for racial and economic equality. The foundation’s first effort is a database that allows people to upload videos showing police misconduct.

LGBT Advocate

At Yale, Selbst was president of the Outlaws, which calls itself “an organization of lesbian, gay, bisexual, transgender and queer members in the law school community.”

She said she once was arrested for questioning a police officer who broke up an Outlaws party during the Yale-Harvard University weekend, as it was the only party halted. The sense of powerlessness she felt that day has driven her to fight back, she said.

“I was thinking this is one of the worst feelings in the world and just to have that realization in one day of my very privileged existence, to know that there are people for whom that’s a daily reality, is just mind boggling,” Selbst said.

Selbst’s mother was an options trader on the American Stock Exchange for 11 years before entering law school. Ronnie Selbst was working as a judicial clerk in Essex County, New Jersey, criminal court when she died in 2005.

Selbst said she has no interest in a Wall Street job like the one her mother had, though she’ll continue to supplement her poker career with outside interests.

“It’s a waste of a lot of potential, intelligence and enthusiasm to just play a zero-sum game your whole life and not do anything else,” she said.