Contrary to USA Today op-ed, Casey was not denied speaking slot at 1992 Dem convention for opposing abortion rights:
As Media Matters for America has pointed out on numerous occasions (here, here, here, here, and here) Casey was denied speaking time in 1992 over his refusal to endorse the Clinton-Gore ticket, not his anti-abortion views. Chicago Mayor Richard M. Daley, Sens. John Breaux (D-LA) and Howell Heflin (D-AL), and five other governors who opposed abortion rights did address the convention in 1992, as detailed in a September 16, 1996, article in The New Republic on the Casey myth. In addition, anti-abortion speakers have spoken at every Democratic convention since 1992, including Breaux in 1996 and 2000, former House Democratic Whip David Bonior (D-MI) in 1996 and 2000, and Senate Minority Leader Harry Reid (D-NV) in 2000 and 2004.
This one fallacy really bugs me.