I guess the issue is that if the other party are zooming off to the right at an alarming rate and have repeatedly in the past acted in bad faith then what's the point.
To my (admittedly biased) eyes, it seems to have worked like this (over a period of months or years)
The Democrats want A, the GOP wants E.
After reaching across the aisle, the Democrats propose a compromise C. The GOP declares that this is unacceptable and that the Democrats refuse to work with then and by the way, their new position is H.
The Democrats reassess and propose F (beyond what the GOP were asking for in the first place). The GOP say this isn't good enough, that the Democrats are traitors who are refusing to work to help the US, oh and by the way, their current position is K.
Chasing a moving target like that with a group who seem to have no intention of accepting anything other than their terms seems like a fools errand to me and results in the Democratic Party adopting policies which run counter to the interests of their core support in an attempt to garner support from groups who wouldn't vote Democrat in any case.
Today's "centre" is the extreme right of 30 or 40 years ago.
