They can't. If they ran on a platform of I'll raise your taxes, I'll release killers from prison, I'll abort babies on demand and I'll kiss Osama's behind, they wouldn't stand a prayer of getting elected dogcatcher in most of the country. The Democrats know their beliefs are anathema to most Americans and yet they realize that if they ran on them, they wouldn't get too many votes. So like Slick Willie, they'll keep triangulating. Its the only means they have off staving off impending political demise.
("Denny Crane: Gun Control? For Communists. She's a liberal. Can't hunt.")