You apparently don’t understand what it means to primary a candidate (from the left, in this case). I’ll explain it for you. The way to get more progressive people in Congress is to primary the existing congresspeople with a more progressive candidate.

Whoever wins the Dem primary in this district will win in the general. It does no good to wait until the general to just vote against the republican and get Jeffries again. You have to find and support a good progressive candidate who is to the left of Jeffries and beat him in the primary. If that doesn’t happen, no one is going to even bother running against Jeffries because they know they won’t beat him in the primary. People have to support support support an opponent.

This is how magats took over Congress. They primaried the hell out of the “traditional” repubs, from the right. They won some of those primaries and lost some. Then sometimes they still lost in the general if their candidate was too far to the right for their district. But they didn’t care because they still won in a lot of others. They kept doing this every election, and the more power the right got in Congress, the more trad repubs just dropped out and didn’t even try to win re-election. Once it gets going it snowballs.

There’s no reason the left can’t do the exact same thing to the Dems as the right did to the repubs. Well, unless it’s already too late now that maga controls the government, that is.