I think it's possible the Democrats calculated that even though the knew their opponents were unprincipled, the electorate would see how bad the Republicans are on this measure and would reject them on that basis. So I think it might be less that they're naive about the nature of their opponents than they are about the nature of what the electorate will and will not accept. If that's the case, with any luck, the realization is landing hard with them and they are developing effective strategies to counter the fascists without selling out their own philosophical souls. That will be a delicate dance for them.