There will forever be an abrasive mark where politics and religion meet.
The reason for this is religion and politics both have their dictates regarding morality. Politics forms the laws whereby society decides what is immoral and at what level it will not be tolerated. Religion does exactly this same thing, but under the authority of God.
This creates friction for many reasons.
Those who refuse to believe in the existence of God, with authority to dictate a moral law, will always see adherence to religious principles as an unnecessary enslavement of humanity.
In a very similar way those who are entrapped in immorality always wish to legalize their behavior. This will create friction with both religion and politics.
There may be friction where two political systems disagree with each other, or where two religious systems disagree with each other. There is surprisingly few examples of this. In regard to morality, people generally agree murder is wrong, family is valuable, and honesty is to be rewarded.
Finally, there will be friction when the political laws and religious laws are in disagreement. As the number of people who reject God increases and as the number of people trapped in immorality increases they will pass laws opposing religious perspectives.
This last case is worth considering carefully. The United States has a bill of rights which protects our freedom of speech, freedom of religion and many other key freedoms. But with the legalized protection of immoral behavior we have created a quandary for our society.
Largely this problem has been addressed by limiting the free speech of religious people. This solution dismisses the bill of rights and undermines the foundation of American freedom. We need a different solution which prioritizes the freedoms in the bill of rights.