What evidence do you have that the average Democratic elected leader is more rightwing than a generation ago?
On abortion, gay rights, womens issues and a range of other social issues, they are demonstrably more leftwing.
And even on economic and labor issues, the average Democrat in Congress is probably more in favor of raising taxes on the wealthy and supporting union issues. There are fewer of them as a percentage of Congress, so they lose more votes on the floor, but they vote pretty leftward.
And on foreign policy, two-thirds of Democrats (126) in the House voted against the resolution authorizing war in Iraq.
So where is the rightward drift?
Nathan Newman