Let me clarify: they are not consciously allying themselves with these conservatives, but they are aligning themselves with them in defense of the centre. Both the GOP and the Democratic Party have a vested interest in maintaining the status quo, with the Military Industrial Complex and all those rich corporations that give evenly to both Democrats and Republicans. For example, the Koch Brothers and many other corporations sat on the Executive Board of the DLC while Bill Clinton was its Chair; many of the donors to the Clinton Foundation and CGI also give heavily to GOP organisations, and even the so-called “Center for American Progress” are funded in part by the UAE — not a very progressive country or government, but there you have it.
In short, it is not in the interest of either the GOP or the Democratic Party to upset the DC establishment that is based on a gravy tarin of money flowing in from Wall Street and Corporate America. And in defending that status quo, these so-called liberals and conservatives find themselves on the same side. They say “politics make strange bedfellows” and this is a case in point.