Exactly on the first part. They moved the debate to the right, not just on that, but on other issues as well. Democrats also won many battles like that, mostly on social issues. I maintain that winning those battles is far more valuable than winning elections.
Now on the second part, you’re only half right. The window can be moved back, but only if there’s an effort to do so. As of right now, Democrats are pretty firm in their conviction that all but the ultra rich should never see their taxes go up. Before they can move the window back to the left, they first have to campaign for tax increases on more Americans. I’m interested in when they will acquire such courage.
Oh, and you mentioned lies, but really the answer to why the Democrats abandoned tax and spend is two words long: Walter Mondale. Ever since his loss, the Democrats have been pushing upwards and upwards the income level that they’ll tax. With Clinton it was about $70,000/yr and upwards, with Gore about $150,000, with Obama $250,000, and in the end he got $400,000 due to resistance in his own caucus. What did the ultra progressive Bill De Blasio promise: $500,000 was it? If even he can’t raise taxes except on the ultra rich, what hope does a normal Democrat have of moving the debate?
SSM wasn’t pushed by politicians, change came about because society became more tolerant of homosexuality. Economic issues don’t function the same way. The public on their own isn’t going to decide to like higher taxes, that is unless government figures out a way to deliver services so awesomely that people can’t wait to pay more for more awesome services.
If the Democrats decide to increase the public’s appetite for taxation and more services, that would actually be a really constructive way to go about it.