Is the current state of politics in the U.S. due to the race of our president?

Many conservatives who held certain positions before Obama was elected had taken the opposite view when he took those same positions. For example, the Affordable Care Act was modelled after Romney's health care law when he was governor. Currently they have tried to repeal it 37 times. In recent times this much acrimony has not been seen, and never before have we had a president with African ancestry. Is there a connection? I am especially interested in answers based on documented facts.