Here's a chat between Luke Mullins of U.S. News' The Home Front and Armando Falcon, former lead regulator of Freddie and Fannie. The conversation covers the how-to part of the federal government taking over the two troubled mortgage finance companies and then the aftermath of winding them down out of virtual existence.

Armando Falcon: How to Nationalize the GSEs – The Home Front (usnews.com)

It's a very informative article on how the whole thing gets unraveled.