Sorry about two Greg Boyd posts in a row, but this is really good.
Greg Boyd - Taking America Back For God
Boyd gave this sermon during the run-up to the 2004 elections, and about 20% of the congregation left. I don't think it's that controversial, I think their election-cycle emotions clouded their decision-making skills.
Of course some far-right Christian organizations would say it is a big deal. Organizations like Focus on the Family, Family Research Council, and Wallbuilders. Of course these organizations definitely lean more towards political organizations than religious ones.