What is it specifically about Keynesian Economics that Democrats find favorable over the Republicans theory of less government intervention and lower taxes?

It's hard to say, b/c the line between the two ideologies has become very hazy over the years.

Nixon once said that, "We are all Keynesians now." Which seems to be the prevailing attitutude today. But even then there's much dissention among the proponents. Alan Greenspan, while critical toward many of Keynes' theories is undoubtably a supporter. Many argue that Bush Jr. and Reagan were Keynesians. And most business colleges, while traditionally proponets of less fiscal and monetary policy, are more or less today centered on Keynesian principles.

I know that U. Texas' School of Business curriculum and theory is mostly Keynesian, while the more conservative Texas A&M business program has traditionally been the opposite.