Every politician looks for a niche where they can combine their passion and their ambition, and advocating for women fits both for New York Senator Kirsten Gillibrand. Her rapid rise in the Senate since being appointed to fill Hillary Clinton’s seat in 2009 has made her a force to be reckoned with on key issues, notably this week on sexual assaults in the military, and along with her increased visibility, Gillibrand has become one of the most mentioned potential female candidates for president—after Clinton of course.

“When I heard her challenge the general or whoever it was speaking for the military, it was pretty presidential,” says Marie Wilson, founder of the White House Project. “She’s not only good on issues and standing up, she’s gotten to be a real force. She is someone who has grown leaps and bounds in the job.”

Gillibrand was at the White House Thursday, one of 15 senators attending a meeting called by Valerie Jarrett to talk about the alarming increase in sexual assaults in the military. Gillibrand called the meeting “super-productive,” and as the first woman to chair the personnel subcommittee of the Senate Armed Services Committee, she has been instrumental along with the increased presence of women in the Senate, Republicans and Democrats, in finally generating outrage about behavior that has been tolerated for far too long.

When Gillibrand first entered the Senate, some downstate women, i.e. women who lived in Manhattan, were wary that she could ever live up to her predecessor. A two-term member of Congress from an upstate rural district, Gillibrand was a Blue Dog Democrat, known for identifying with right-of-center positions, notably on guns. The NRA gave her a 100 percent rating, and without it she probably couldn’t have been elected in the Republican-leaning district.

“I still support Second Amendment rights, but you can’t meet a parent who lost a child to gun violence and not do anything,” she said in a telephone interview with The Daily Beast. Gillibrand is now a reliable vote for gun safety, and says she shouldn’t have disclosed to a reporter for Newsday in 2009 that she and her husband kept guns under their bed. “It was a rifle; it was in its box; it had no ammunition; it was stored under our bed because it was very long,” she said.

Gillibrand has since won two elections handily in New York, and she has earned respect for her hard work and steely diligence. “Members labor, or even belabor what the problems are,” says Neera Tanden, president of the liberal-leaning Center for American Progress. “She moves immediately to ‘how do we get it done.’ She’s very strategic.” Stephanie Schriock, president of Emily’s List, says, “She’s really taken on the mantle for being the champion for women and families,” beginning with leading the fight in 2010 to ban drop-side cribs when she was “just getting her feet beneath her” in the Senate.

She hasn’t forgotten other women in her fast rise: in 2011, she created Offthesidelines.org, a political action committee dedicated to getting more women to run for office, and to get engaged in the issues. “It’s more of a call to action,” she says, urging women to sign petitions and take up causes like paid family leave, in addition to funding campaigns. She’s raised $1 million for candidates since founding the PAC, including $100,000 for Elizabeth Colbert Busch’s losing race in South Carolina.

Gillibrand’s advocacy for women is a passion that dates back at least to when she was a young lawyer living in Manhattan. Ann Lewis, a longtime Clinton confidante, remembers Gillibrand coming into the Hillary-for-Senate office in Herald Square in 1999 asking what she could do to help. “A lot of people come through a campaign and say they want to work, but she kept coming back and she actually did what she said she would do,” says Lewis. “She is a natural born networker and advocate.”

A business associate who did not wish to be quoted pays Gillibrand the ultimate compliment: “She’s very normal. She’s breezy in conversation, not guarded. She knows what’s happening in the world beyond what’s happening in Congress—and she’s clearly a mom.” Asked about the mom part of her life, Gillibrand, who at 46 has two young children, says, “I’m totally lucky because I run my office and I get to set my schedule.” No meetings before 9 so she can take the boys to school, or between 5 and 7, so she can pick them up, get them dinner and to bed.

“I had a lot of women role models in my life,” says Gillibrand, citing her grandmother, who founded the Democratic Women’s Club in Albany, and her mother, a trailblazer as one of three women in her law school class, and then of course Hillary Clinton. An Asian studies major at Dartmouth, Gillibrand knew how groundbreaking it was for Clinton to say in Beijing in 1995, “Women’s rights are human rights, and human rights are women’s rights, once and for all.”

Gillibrand has gone through doors Clinton helped open, and there’s no way that she would step on Clinton’s toes, as if anybody could. She wants Hillary to run and has told her that, but if Hillary doesn’t run, the smart money in Washington sees Gillibrand as the first woman in line.

In the meantime, she is proving to be an adept legislator, having played a key role in pushing through the overturning of Don’t Ask, Don’t Tell in a lame-duck session when many of her colleagues thought it was hopeless. Her persistence is already the stuff of legend. She reportedly was so relentless in fighting for health benefits for New York’s Ground-Zero responders that one key senator told her he would vote for it just to get her off his back.