The DNC’s right turn happened under Reagan due to the losses of Carter, Mondale, and Dukakis, but actually the genesis of this movement was the Democratic massacre of George McGovern in 1972. By the way, my politics has always been McGovernite Democratic Party liberalism, for all of you idiots out there who keep insisting I’m a rightwinger or a Republican.
This group decided that these losses showed that the US was a rightwing country and if the Democrats didn’t want to lose forever, they would have to turn into a rightwing party too. So they set about to do just that. Clinton was their original Frankenstein creation.
I found the website of this group some years back and found documents laying out the destruction of Social Security and Medicare! The documents argued that these were socialist programs and the whole world was turning away from socialism after 1989 and the fall of the USSR and Eastern Bloc. This event indeed did herald a neoliberal fever for some time under Reagan, Thatcher (may she burn in Hell forever), etc.