That *phrase* has a history (it is not unique to MSW).  Here is a statement by a professor that uses that phrase:  http://religionandpolitics.org/2013/02/05/we-need-less-religion-in-our-politics-and-less-politics-in-our-religion/
MSW followed that up with this opinion piece - https://www.ncronline.org/blogs/distinctly-catholic/prothero-religion-politics
I agree more with Prothero than Wear.