Following the money behind the anti-science madness in North Carolina's US Senate race

Institute for Southern Studies Executive Director Chris Kromm appeared on the MSNBC news show "All in With Chris Hayes" on Wednesday to discuss what Hayes described as "what may be the most-watched upcoming U.S. Senate race in the country" -- the crowded Republican primary to select the challenger to Democratic Sen. Kay Hagan.

There are eight Republicans battling to take on Hagan, and this week there were two debates between the four leading candidates: North Carolina House Speaker Thom Tillis, physician and Tea Party activist Greg Brannon, nurse practitioner Heather Grant, and Mark Harris, pastor of First Baptist Church of Charlotte and president of the Baptist State Convention of North Carolina. The primary will take place on May 6; if no candidate wins more than 40 percent of the vote, a runoff between the top two vote-getters will be held on July 15.