For about a century, politicians tried and failed to create a program offering universal access to health care in America. With the passage of the Affordable Care Act (ACA) in 2010, it finally happened. But while the bill was widely nicknamed Obamacare, it wouldn’t have gotten done without the Speaker of the House, Nancy Pelosi. When some White House advisers wanted to quit, Pelosi urged President Obama to keep going, and worked to convince her colleagues until there were enough votes: “If the gate is locked, we push open the gate. If we don’t push open the gate, we’ll pole vault over it. If that doesn’t work, we’ll parachute in. But we’re not letting anything stand in the way of passing affordable health care for all Americans.”

The ACA was just one of many achievements Pelosi racked up during her terms as the first woman Speaker from 2007 to 2011, including protections against pay discrimination for women, allowing gay people to serve openly in the military and saving the economy from financial collapse. When her party lost the majority in 2010, she refused to quit, and as minority leader, she still found ways to be effective, protecting the ACA and Obama’s Iran nuclear deal against massive pressure from the right. Even many in her own party thought her time had passed—Republicans depicted her as an extreme liberal partisan, and many Democrats worried her polarizing persona was a liability for their party. But in 2018 she led them back to the majority and became the first Speaker in six decades to return to the Speakership after losing it. Today, Democrats hail her for her tenacity in standing up to President Trump, protecting America’s system of checks and balances, and masterminding the third presidential impeachment in the nation’s history. —Molly Ball

Ball, TIME’s national political correspondent, is the author of the forthcoming biography Pelosi

This article is part of 100 Women of the Year, TIME’s list of the most influential women of the past century. Read more about the project, explore the 100 covers and sign up for our Inside TIME newsletter for more.