This past Election was The United States, SPD/Communist moment. With fascism knocking, the Democrats decided not to align with the Left.

Next one's just a bit

It’s an extremely stretched, you have to squint to see it, analogy, but I guess Nader would be the closest figure. The Dems leveraged his 2000 campaign to convince libs and the center-left that any failure of the Dem establishment is the fault of ideological leftists and ergo any leftist who doesn’t bend the knee is not to be trusted. 20 some odd years later, here’s Kamala pitching to “Liz Cheney Republicans” rather than offering an inch to the left.

Nobody that's similarly prominent enough to be compared to even a wannabe Rosa tbh.