I have a little different take on this. First, I have no respect for Obama, his actions or his policies. That being said, no teacher should impose their politics on students no matter their beliefs.
Look at the leftist brainwashing taking place on college campuses. The country is raising a bunch of ignorant people devoid of basic knowledge.
Neither side should be allowed to do this.
Bashing of politicians is perfectly acceptable if you speak the truth, not made up drivel.