Thomas Carper, the low-profile junior senator from Delaware, tries to walk the middle of the road on abortion. He was rated at 55 percent pro-choice by NARAL in 2006, but he was one of the 17 Democrats who voted to ban partial birth abortion three years earlier. Carper said after the court upheld the 2003 bill: "I think a number of people who voted for it thought that the court would ultimately strike it down."
There is something very smarmy about voting for a bill that you think is unconstitutional in the hope that you can have your cake and eat it too when the Supreme Court knocks it down. And to be bipartisan, plenty of Republicans, including President Bush, did that with the Bipartisan Campaign Reform Act, commonly known as McCain-Feingold.
This is from a good post by Betsy.