Low Information Politician?

One of the staunchest promoters of the "defense of marriage" act has suddenly come out in favor of  same sex marriage.  Ohio Senator Rob Portman has reversed his former position because he finds out that his son is gay, and suddenly he has developed empathy towards others.  Something like that happened with Dick Cheney too.

It seems we are all just one family member or valued friend from changing our fundamental beliefs.

In the light of such dramatic revelations, how can we be sure of anything that we believe?