Senator quits because other senators are mean

Senator Evan Bayh of Indiana is using the lamest reason ever not to seek re-election:

Two weeks ago, the Senate voted down a bipartisan commission to deal with one of the greatest threats facing our nation: our exploding deficits and debt. The measure would have passed, but seven members who had endorsed the idea instead voted ‘no’ for short-term political reasons…Just last week, a major piece of legislation to create jobs – the public’s top priority – fell apart amid complaints from both the left and right. All of this and much more has led me to believe that there are better ways to serve my fellow citizens, my beloved state and our nation than continued service in Congress.

So if I understand the Senator correctly, he is quitting because other senators aren’t playing fair. Why isn’t Bayh be concerned that he will be replaced by a partisan, rather than the moderate he claims to be? Are we supposed to be impressed by his decision? Seems to me it would be far more courageous to stay and fight for what you believe is right than to quit because governing is hard.