Is the battle for the GOP presidential nomination about history? Or is it about math? Santorum may be getting big headlines with his primary wins, but it's Romney who is advancing further to the magic 1,144 number. And more defeats mean more pressure on Gingrich to pull out. Plus: a tribute to the late Peter Bergman of Firesign Theater. NPR's Ron Elving and Ken Rudin have the latest in this week's political roundup.