If his constituents had wanted all abortion to remain legal and he had voted against the partial birth abortion ban, would that vote still be "honorable" because he was doing what his constituents wanted? If he had cast this "honorable" vote, would you accuse him of a "flip-flop" if he then tried to campaign as an opponent of abortion? Partial birth abortion is an extreme case, but what if the record weren't so extreme? Would he still be "honorable" for voting with his pro-abortion constituents and then trying to claim that he can be a pro-life candidate?
I don't have a big problem with Fred Thompson on the abortion issue, but what you've tried to describe as "honorable" is no different from what Mitt Romney did in Massachusetts. Mr. Romney faced an electorate that wanted abortion to remain legal. Rather than trying to fight that battle at that time, he campaigned as someone who wasn't going to change the right to abortion in any major way, and he that's how he governed. He did a few minor things against abortion, but he generally represented his constituents. Many of Mr. Thompson's supporters are attacking Mr. Romney for approaching the issue that way.
The point that I'm making is that if Fred Thompson had lived in Massachusetts or some other liberal state, his record on abortion would be no different from Mr. Romney's. At his core, he's no more pro-life than Mr Romney is. If conservatives are going to choose among the "top 4" candidates, they are being foolish to view Fred Thompson as someone who is significantly more conservative than the other three. As the article says, Mr. Thompson hasn't stood forward as a conservative champion. He's not a bad guy. If he's nominated, I'll support him with my vote and maybe with time and money. If he's elected president, I hope he'll do a good job. However, he doesn't come to the campaign as someone who deserves the label of strong, consistent conservative.
Bill