Katie Porter, a freshman Democrat in Congress, couldn’t have known when she wore a batgirl Halloween costume to Donald Trump’s impeachment vote in October that she would soon have the chance to help rescue millions of Americans during a global pandemic. But as Trump’s administration badly mishandles the deadly coronavirus outbreak, Porter has unexpectedly emerged as a true hero in a spiraling crisis.

The California congresswoman, a former law professor and single mother of three who flipped a GOP district in 2018, had watched as the United States fell far behind other countries in terms of responding to the pandemic. South Korea, for instance, has tested over 200,000 citizens, while as of Tuesday, the U.S., which had its first known case back on January 21, had only tested 6,500. Germany, South Korea, and the UK quickly set up free drive-thru testing for their citizens, while Americans have been getting denied tests at the emergency room and then stuck with a $10,000 bill anyway. Many Americans cannot even afford the out-of-pocket cost for the coronavirus test, which can add up to more than $1,300, much less the hospital stay. Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, told Congress on Thursday that the U.S. healthcare system is simply not set up to handle rapid, widespread testing during outbreaks: "It is a failing. Let’s admit it.”

So Porter took matters into her own hands. Having studied at Harvard Law under Elizabeth Warren, she has become exceptional at grilling powerful men in Congressional hearings and exacting results. And it took her only five minutes of questioning at the coronavirus hearing on Thursday to compel the chief of the Centers for Disease Control, Dr. Robert Redfield, to use his legal authority to make testing for the virus free for all Americans.

Porter had done her homework. She’d calculated the cost of the full battery of coronavirus tests to be $1,331—which is out of reach for many low-income patients. She’d also found an obscure federal statute that gives the CDC chief the authority to immediately waive the cost of that test for everyone. After laying all that information out on a whiteboard at the coronavirus hearing, she asked Redfield pointedly: “Will you commit to the CDC, right now, using that existing authority to pay for diagnostic testing, free to every American, regardless of insurance?"

Redfield tried to squirm out of answering the question several times, saying he would “review it in detail” with the CDC and “work with HHS to see how to best operationalize it.” But Porter kept reclaiming her time and interjecting—“Not good enough” and “Yes or no?”—until the CDC chief eventually relented. "I think you're an excellent questioner, so my answer is yes," Redfield said.

It was an absolutely remarkable display of effective politics that left the Beltway stunned. “Rarely has a member made more with five minutes of his or her time,” tweeted Sam Stein, politics editor of The Daily Beast.

Indeed, the last time a member made almost as much with her few minutes of time in a congressional hearing, it was also Katie Porter. Last March, she skewered Wells Fargo CEO Tim Sloan over the bank’s defrauding of its customers, caught the bank in a lie with her signature prosecutorial questioning and forced Sloan to resign in shame two weeks later. Two months later, she exposed Housing and Urban Development Secretary Ben Carson’s complete lack of knowledge about foreclosure properties when she used an acronym—REOs, or real estate owned properties—that he confused for oreo cookies.

The thing about congressional hearings, as anyone who’s covered them knows, is that they are generally pointless exercises in which nothing really happens. Lawmakers occasionally “grill” witnesses in hopes of getting a few good soundbytes, but these events are mostly just kabuki theater; the law writing and the votes happen elsewhere. Porter, though, has in her very first term managed to do in these hearings what lawmakers have been pretending to do in them for decades: speak truth to power, generate actual results, and enact change. She has arguably become one of the most effective members of the entire House of Representatives.

The great irony is that during Porter’s campaign, she was forced to defend her fitness to serve in Congress as a single mother who survived domestic violence. In April 2018, when she was still a candidate in a tough primary, the down-to-earth Iowa-born professor sat across a table from me at a Washington, D.C., Marriott hotel and sobbed for a full hour as she recounted the story of her ex-husband’s physical and psychological abuse. He had allegedly ripped dental floss out of her hand one night and shattered the faceplate on the light switch with his bare hand because he said she was “brushing her teeth too slowly.” She said he shoved her into a wall, threw things at her, called her a “dumb bitch” in front of their three young children, and would pound so hard on her bedroom door at night that she had to prop a chair against it to keep him out.

Porter successfully obtained a restraining order against her husband in 2013 and briefly went into hiding with her children. And five years later, while she was running for Congress, that court document became the subject of a whisper campaign in the competitive Democratic primary for California’s 45th congressional district. Several Orange County delegates told Porter they’d heard there was something “disqualifying” in her divorce records, and she wasn’t sure what that meant until a donor to one of her opponents called her “Katie ‘Restraining Order’ Porter” on Twitter.

On top of that, Porter told me voters would frequently ask her how she could handle being a congresswoman as a single mom. “People come up to me and say, ‘If you win, who will care for your children?’” she said. “I’m a tenured professor―I’m doing it. I had three babies on the tenure track and took no delay. I know how to raise kids and work. Half of all the moms in America are single moms, and there should be more of us in Congress.”

One advantage of having a regular, working single mother in Congress—Porter is the first single mom raising young children while in office—is that they know quite a bit about health care and what it costs, especially at a time like this. They are used to having to multitask, be extra organized and work twice as hard as people with more support. When she tells the CDC chief that “fear of these costs are going to keep people from being tested, from getting the care they need and from keeping their communities safe,” she is speaking from experience and from the heart, and that’s part of what makes her questioning so powerful and effective.

It’s a stark contrast to the response of Republican members of Congress like Texas senator Ted Cruz and Florida congressman Matt Gaetz, who have been more concerned with protecting Trump’s reputation throughout the crisis and helping the president downplay it, even as they themselves have to go into quarantine, than considering how they might use their power to help stop the epidemic from spreading. Gaetz mockingly wore a gas mask on the House floor to make fun of the media for overhyping the crisis. Cruz posted a video of himself defending Trump from his home isolation and lamented having to miss an Eagles concert.

Porter is focused on expanding the accessibility of coronavirus tests for all people. In addition to securing a commitment from Redfield, she is leading the effort in the House to pressure the administration to allow academic medical centers to assist the rest of the medical community in testing new patients. No one should be surprised that in this spiraling public health crisis, it took a single mom brand new to Congress to find the empathy, grit, and preparedness to step up and show the country what a leader should look like.