Evangelicism has been strong since the founding, but it is more brazenly political now than it has been historically. There is actually a legal requirement for churches to stay out of politics in order to maintain their tax-exempt status. The enforcement of that has gotten more lax over the last few decades.

With regards to information about entanglements between religion and business, start with the LDS church, whose business entanglements are well documented.

But the journalism about the more general problem is is not very comprehensive, probably because it is a very fraught topic.