The corporate moguls who run the US empire and its political processes are not fools. So when the Republican party deliberately pushes forward certifiable clowns like Michelle Bachman, Richard Perry, Herman Cain and Rick Santorum as its presidential contenders, we can be certain that matters are not quite what they seem. These pandering lunatics are only inmates of the asylum, which is run by the corporate entities that fund the careers of Democratic and Republic politicians alike --- the energy and insurance industries, corporate media and real estate, military contractors, and of course, Wall Street.
In the words of economist and financial historian Michael Hudson , the job of corporate American politicians is not to enact the policies their voters want. The corporate politician's job is to deliver those voters, those constituencies to their campaign contributors, so they can enact the policies their financiers desire. The fact therefore, that Democrats compared to Republicans, and sometimes even Democrats compared to other Democrats appeal to varied groups of voters accounts for why they sound different from each other. But the fact that they all depend on the same class of wealthy corporations and individuals to finance their political careers means that no matter what they tell their voters, the policies they enact once in office are pretty much the same.
This accounts for the fact that although the Democratic presidential candidate won his nomination by telling voters he opposed the war in Iraq, by the time he sewed up that nomination, he was appearing on the Bill O'Reilly show to praise the war in Iraq and endorse the Cheney-Bush “surge” . It explains why candidate Obama, after promising (but mostly only before labor audiences) to renegotiate NAFTA, walk a picket line and pass legislation that would make more unionization possible, president Obama pushed to extend “free trade” agreements everywhere, cracked down on federal workers, demonized teacher unions and more. It explains why Obama literally claims to walk in Martin Luther King's footsteps when it suits him --- on the campaign trail he declared himself “Joshua”  to Dr. King's “Moses” --- but manages to ignore black unemployment and mass incarceration, the wave of foreclosures which are inordinately concentrated among nonwhite households, and maintains the US position as in King's words “...the number one purveyor of violence in the world today.”