Mostly used by preachers who want to discourage their congregants from getting involved in politics, usually left-leaning pastors.
The problem is that as a Christian, I am required to be responsible to Christ's edicts in all facets of my life and that includes politics.
Absolutely true - as for a citizen...but when you are a church and have signed on with an agreement with the gov't about "tax free" benefits - then you have made an agreement and can't have it both ways.
Any church who wants to fore go the tax-free benefits can preach the rafters off with political sermons.
There is a difference - and that's where 'render unto Caesar' comes in.