In the late 1970s, after getting her law degree from the University of Missouri—and paying off her student loans after a successful streak on a game show—Senator Claire McCaskill became an Assistant Prosecuting Attorney in the Jackson County, Missouri Prosecutor’s Office. For a time, McCaskill told me, she was the only woman in the prosecutor’s office—which once led to her taking an older man to task after he said there was “no point in us trying” a rape case where the defense was consent and the victim was on birth control.

McCaskill remembered, “I just looked around, thinking, is everybody going to laugh? Is this a joke? And I realized that he was serious.” She asked him, “'hypothetically, Larry, if I’m taking the birth control pill, does that mean if I go out tonight, that anybody can rape me and they get away with it?’ and he got a little uncomfortable and embarrassed.”

From her time as a prosecutor, to her last election—when her opponent expressed his belief that a woman can’t get pregnant if it’s a “legitimate rape”—to her current status as Washington’s leading sexual assault reformer, almost every aspect of McCaskill’s career has revolved around sex crimes. And speaking to her, it’s easy to understand why.

McCaskill is still haunted by cases she tried in the Jackson County office. As she recounts the details, her usually bright and authoritative voice grows softer, she speaks slower, she pauses to close her eyes or face the ceiling—over 35 years of hearing gruesome details from cases of sexual violence has clearly not caused her to detach or desensitize.

The memories of one case in particular, McCaskill said, remain vivid. It was very early in her career, and it was one she lost.

McCaskill told me the victim had willingly gone home from a bar with the defendant—but then things took a dark turn. The victim’s screaming alerted the defendant’s neighbors, one of whom broke into his apartment—but the defendant ran out.

When McCaskill didn’t get a conviction, she blamed herself entirely. “I felt like it was my fault that the jury had acquitted the defendant,” she told me. “I felt so badly that I tried to stay in contact with the victim… For many years the victim sent me a Christmas card. And it was like my touchstone every year at Christmas when I’d get this Christmas card, because I’d feel better that she had forgiven me. Because I felt so personally responsible.”

McCaskill was then discouraged from taking a different case where consent was again the defense—this time involving a stripper and three men. The victim went home “to party” with the three men, McCaskill remembered. When they ordered her into the bathroom to “clean up” before they had more men come over, the victim escaped. “She threw herself out of a bathroom window, naked, and ran down the street to get away,” McCaskill said. “I mean, went through glass to get out of the bathroom.”

McCaskill took the case. In the hallway outside of the courtroom, she remembered, the “ringleader” of the three men “would say things to me…like ‘I know you want it, you all want it,’ and it took everything I had to be professional and ignore him…I had internalized how angry I was at these three men for the way they had treated this woman and the way they saw her as something unworthy of the protection of the law.” All three men were convicted.

McCaskill was first elected to the U.S. Senate in 2006, defeating Republican incumbent Jim Talent, after a long career in Missouri state politics, wherein she served in the State House, as the Jackson County Prosecutor and the State Auditor and ran, unsuccessfully, for governor in 2004.

In 2012, McCaskill was in a highly competitive race for re-election against Republican Todd Akin. Then, a stroke of luck for McCaskill: Akin did an interview with KTVI-TV, where he said that it’s “really rare” for women to get pregnant as a result of being raped because “if it’s a legitimate rape, the female body has ways to try to shut the whole thing down.”

McCaskill pounced, calling Akin’s statement “so outrageous.” Akin was almost immediately denounced by everyone from Mitt Romney to President Obama, and McCaskill was re-elected by 54.7 percent to 39.2 percent.

On McCaskill’s office wall hangs a cartoon by the Kansas City Star’s Lee Judge which depicts Akin wearing blinders, with the caption, “two Senate candidates offer different visions.”

But ironically, it’s McCaskill who is accused by critics of having her own set of blinders—about her signature issue, sexual abuse.

In January of this year, McCaskill, who serves on the Armed Services Committee, introduced the Victims Protection Act, which aims to shield survivors of sexual violence in the military by, among other things, providing each survivor with their own lawyer and preventing military members to use the “good soldier defense.” But the bill didn’t do the one thing victims’ advocates were asking for the most: take the cases out of the traditional chain of command. How, the advocates asked, could the survivors’ bosses—who arguably have a vested interest in keeping cases of sexual violence quiet—serve as judge and jury?

The legislation passed, but only after a nasty battle in which McCaskill found herself opposed by many liberals, victims’ advocates and, perhaps most memorably, Senator Kirsten Gillibrand, whose own legislation would ultimately fail to overcome a Senate filibuster. Many blamed McCaskill’s and her competing bill for killing Gillibrand’s more far-reaching legislation, which would have taken sex assault cases outside of the chain of command.

McCaskill believed she was following the right approach. But to vocal opponents, the former sex-crimes prosecutor became a “roadblock” to meaningful legislation who was “unwilling to compromise.”

In a particularly vicious incident, Susie Tompkins Buell—a top Dem donor who counts Hillary Clinton among her closest friends—directed fire at McCaskill by quoting Madeleine Albright at a fundraiser, “there’s a special place in hell for women who don’t help other women.”

But Buell may have just been trying to do right by Clinton. McCaskill was allegedly on Clinton’s 2008 “enemies list” for comments she made during an appearance on Meet the Press in 2006, when she told the late Tim Russert that Bill Clinton was a “great leader, but I don’t want my daughter near him.” A friend of McCaskill’s reportedly told the authors of a forthcoming book on Clinton that she immediately regretted the remark, which brought her “to the point of epic tears.”

Adding insult to injury, McCaskill was one of the first Senators to support then-Senator Barack Obama for the presidency.

Perhaps in an effort to repair some of that damage, McCaskill endorsed Clinton for 2016 three years early, declaring in 2013, “I am proud to announce that I am Ready for Hillary.”

McCaskill has made an alliance with Gillibrand, too. Together, they are in the very beginning stages of figuring out how to reform how colleges respond to rape on campus.

Both McCaskill and Gillibrand are adamant that they are working together—they even shared an umbrella recently to hammer the point home. But this issue, McCaskill told me, is even harder than that of military sexual assault. “This is more difficult because you’ve got more moving parts,” she said.

To make sense of it all, McCaskill is holding a series of roundtables with experts on the issue. On Monday, she held the first of them (including Sen. Tammy Baldwin), which was dedicated to the Clery Act (one of several laws, including Title IX and parts of the Violence Against Women Reauthorization Act of 2013, which directly applies to campuses).

The panel spent close to two hours discussing the specifics of the issue, like how a university should be punished for failing to comply with existing laws, what kind of database should exist to inform prospective or current students and families about a school’s crime statistics, and whether or not school officials should be forced to notify local law enforcement if they are made aware of a rape.

Back in her office, McCaskill was reluctant to reveal the exact list of what she hopes to accomplish legislatively, “because it probably will change,” and, she said, “we’ve got to be careful here, because we can over-legislate. We can be so busy putting requirements on universities that they are checking boxing instead of making sure students are safe.”

Ultimately, McCaskill said, “I try to look at everything through the perspective of the victim.”

Behind her glasses, McCaskill’s eyes widened. “I’ve seen a huge sea change in this area,” she said. And that’s the reason why McCaskill gets frustrated when people dismiss the idea that law enforcement can help fix the problem, as a member of the roundtable had done the day before. “I personally know how many dedicated prosecutors are out there in this country that do nothing but these kinds of cases, day in and day out, with a great deal of professionalism and excellence.”

“That’s why I have this job,” she told me. “I wanted this job so that I could change things and I could bring the force of the law—I could bridle that—in a way that is really positive for the problems that I care a lot about, and I care a lot about this problem.”