If you are represented by a liberal in the house and he/she votes yes on the AUMF

[Scootaloo]

26. They're called "primaries," Baldguy

See, that's when, prior to the main election, the parties have their own votes to see who the given candidate from their party will be.

In the primaries, the voters belonging to that party get to vote according to who they feel will best represent their interests and the party as a whole.

As far as I am aware, Republicans do not often seek nomination from the Democratic party, nor vice versa. i'll grant that it's not impossible, if say all the candidates stepping up for a party are so far from that party that the only choice is to endorse the opposition. But it's really, really, really uncommon.

So, would I throw out an incumbent Democrat and replace them with a more liberal candidate? Absolutely. AUMF or no, in fact, the more liberal the better.