My thinking is pretty simple on this topic.  They should not mix.

I have little regards for politics because it is dirty, underhanded and attracts people hungry for power and prestige. None of the qualities that make a typical politician are qualities one would want to see in a truly religious or spiritual person.

To me, politics and religion are opposites.  When any established religion tries to place their politicians in office it tells me that they are not seeking religious reform, they are seeking religious ADVANTAGE.

While our founding father's were religious men and Christians, they also understood from personal experience, why people were fleeing to the America's to escape religious persecutions in their homelands.

Because of their understanding they chose to exclude the "establishment" of any particular religion in the new nation they were building. They "allow for" all religions and protected "all" religions including those they personally did not belong to or support.  They acknowledged that their Christian beliefs were such that it was important to recognize other beliefs as having a valid and equal place to exist under our flag.

One only has to look to countries ruled by religious leaders to understand the dangers. Iran, Afghanistan, the former Soviet Union to name three; countries where a person could actually be sent to prison, or worse, for practicing any non-state religion.  We are at war with people who attacked us based, in part, on their hatred of Christianity.  

Remember the Inquisition? In a time when Christianity ruled much of Europe, people were killed if they refused to convert.

The only role government should serve with regard to religion is to insure and protect everyone's right to practice, or not, any form of religion they choose.

I have a profound distrust of any religions group supporting any politician. To me that is just short of making a bargain with the devil in exchange for a religious advantage.