Maybe it’s because he doesn’t map culturally as a liberal. When the Democratic Party wants to prove to the nation – or maybe to the media – that they have non-threatening, common-sense, middle-America values and ideas, they turn to the Oracle of Omaha. Congressional Democrats use him as an identifier for their signature tax policy, the Buffett rule. A couple weeks ago, Hillary Clinton campaigned with Buffett in Nebraska. In 2008, when Barack Obama needed a general election validator to soften the liberal edges played up by his opponents, he touted an endorsement from Warren Buffett in his first national ad.