Bernie hasn’t always been the de facto progressive leader.

That’s right. Before Bernie, there was… Elizabeth Warren. In 2015, when the Democratic primary for the 2016 presidential race was starting, liberal groups were literally begging for Elizabeth Warren to run. Liberal groups such as MoveOn and Democracy for Action were raising millions to convince Warren to run, even as she continually said no.

This didn’t change when Bernie entered the race. These groups welcomed a strong progressive in Bernie to the race, then in the next sentence continued for their push for Warren to enter. When asked why they supported Warren over Sanders, these groups touted Warren’s strong progressive record and outspokenness, her leadership on issues regarding wealth inequality and battling Wall Street, and how she was a “better package” for the progressive message than Bernie.

Compare that to now, where Warren is seen as a more moderate Bernie. Some Sanders supporters refer to Warren as Bernie-lite. Some more extreme supporters refer to her as a corporate sell-out. But this characterization of Warren as a Bernie copycat is ignorant of the history of both Warren and the progressive movement. It verges on revisionism, erasing much of the progressive work that Warren has lead and championed for years.

But why was Warren the progressive leader? Both Sanders and Warren were United States Senators at the same time, they shared much of the same platform, they both railed against wealth inequality and a rigged system, so why was Warren the “breakout” progressive?

The answer goes back to MoveOn’s characterization of Warren as the “better package” for the progressive message. Warren showed a strong knack for getting things done. Before she was even in the Senate she railed against the Bankruptcy Bill, oversaw the $700 billion bailout of big banks, and established the CFPB. Then she was elected to the Senate where she exercised outsized influence for a first-term junior Senator. She pushed for ideas that she believed in, even when that broke with the Democratic leadership. She organized 20 Democratic senators (and Sanders) to break with the party over a change to Dodd-Frank that she saw as harmful. She aggressively questioned CEOs of big banks over shady business practices as displayed in her famous questioning of Wells Fargo CEO Stumpf, and even argued for the jailing of CEOs such as Stumpf for defrauding customers.

That isn’t to say Sanders hasn’t been a strong progressive his whole life. He has. But his record is more ideological than accomplishment based. The choice now is the more ideologically pure candidate, or the candidate with more concrete accomplishments. Only time will tell which lane the political moment favors.