I don’t think DeMint was into Romney as anything but a slightly preferable alternative to McCain. Given that we were already plunging into economic depression at the time, which would you choose - the successful businessman, or the lifelong politician who admittedly knew nothing about economics?
Not true. DeMint endorsed Romney in January 2007, long before the field was final.
The first thing that comes to mind is DeMint knew a whole lot more then about Romney than I do even now, and more than the vast majority of us know.