Oddly, Kruse's narrative does not square with his title. Roosevelt-hating corporate leaders may have hoped religious ardor could be used to overcome the creeping welfare state gradually created under the New Deal, the necessities of World War II, and the Truman administration's policies. But their militant "spiritual mobilization" only took root as a broad, vanilla Protestantism. Dwight Eisenhower may have been personally a believing old time Calvinist, but the experience of holding together the fractious and diverse European war effort against Hitler had made him into an inclusive leader who affirmed all the country's religious communities. His national vision was all in favor of pointing citizens to God; during his tenure the campaigns to add the phrase "under God" to the Pledge of Allegiance and "in God we trust" to coins succeeded with bipartisan acclaim. But this was no sectarian assertion; it was rather a sort of "ceremonial deism" that made vague reference to a God but offended few.
I'm of an age to remember clearly when the phrase "under God" was added to the Pledge. I can't say I was either distressed or impressed by the addition. The daily elementary school rote recital while facing a piece of cloth failed to impress me in the 2nd grade; throwing in the Deity didn't change that. The 1950s were a time when many people lived quite happily while going through the motions, reasonably content if they were white. The generic religion of the state didn't impress or differentiate much.
This changed in the 1960s when both white rule and largely uncontested empire began to crumble. Kruse dates the origin of the contemporary religious right to the Supreme Court decisions in 1962 and '63 that treated "non-sectarian" prayer in schools as an unconstitutional forced establishment by the state of a religious practice. (This is two decades earlier than Randall Balmer suggests; he makes a persuasive argument that the religious right took off for fear of federal efforts to defund white supremacist schools.) Most mainline Protestants (including Baptists who were historic champions of church-state separation) and the tiny non-Christian faith communities, reconciled with these decisions quite easily.
As the justices extended their first decision to end prayer in schools more broadly, the mainline Protestant denominations and their friends clustered in the National Council of Churches continued to support the court's moves to get the government out of the religion business. Opposition was led by the Roman Catholic hierarchy and some more right wing fundamentalists and evangelicals. Most citizens were shocked by the rulings; if they'd ever thought about public prayer at all, they considered it non-objectionable. In that decade, perhaps for the last time, the traditional Protestant leadership's untroubled views prevailed over politicians who sought to ride the school prayer issue to victory. Kruse tells this story in some depth; for me this was the most interesting segment of the book.
When he moves on to Richard Nixon's alliance of mutual convenience with the evangelist Billy Graham, he's on turf better told by such authors as Rick Perlstein.
I'm left appreciative of Kruse's history; this is terrain worth his deeper dive. But what happened that the book came out with a misleading title?