John King, along with Arizona State University students playing the parts of Ron Paul, Rick Santorum, Mitt Romney, and Newt Gingrich, is doing a run-through today ahead of tonight’s GOP debate in Mesa, Arizona. This is the 20th, and likely final primary debate. The first face-off on Fox News last May, also featured four candidates — only one of whom, Ron Paul, is still in the race. The other attendees were Herman Cain, Gary Johnson and Tim Pawlenty.

Tonight’s debate will feature the candidates at a table instead of podiums. Playbook reports CNN last used this set-up for a GOP debate on Jan. 30, 2008, at the Reagan Library. Sitting at the table then were candidates John McCain, Mike Huckabee, Romney and Paul.

The Arizona debate airs on CNN at 8pmET.