George Mitchell, who successfully negotiated the Good Friday peace agreement that ended years of sectarian conflict in Northern Ireland, is leaving his post as U.S. Mideast envoy -- unable to duplicate his Ulster triumph.  It wasn't exactly his fault; the deck simply was stacked against him.   President Obama and Palestinian President Mahmoud Abbas saw to it that there was nothing left for him to do.

Mitchell's assignment was to mediate an end to the Israeli-Palestinian conflict, but almost from the beginning he was blindsided by his boss in the White House and by Abbas's refusal to negotiate a realistic peace agreement requiring concessions by both sides.

Obama was not content to leave Mitchell to lay out his own precepts for an accord.  Instead, the president imperiously demanded that Israel first agree to freeze construction in the West Bank and East Jerusalem as a prelude to direct negotiations -- a one-sided gift to the Palestinians.  Obama's warped approach -- requiring Israel to make unilateral concessions as the price of getting Abbas to the negotiating table -- was bound to fail.  And it did.  Israeli Prime Minister Netanyahu agreed to a good-faith negotiating process, but without preconditions.  For his part, Mitchell was handcuffed and second-guessed by his own boss, who wanted a peace trophy for himself.

With Obama landing hard on Netanyahu, Abbas turned equally intransigent and demanded a permanent freeze of construction in East Jerusalem and the West Bank, without any corresponding compromise or concessions on his part.  After all, Abbas couldn't be seen to be less demanding of Israel than Obama was.

The result was a U.S. diplomatic path to nowhere.  The peace process became frozen.  Obama was forced to backtrack, while Abbas turned his back on Obama and publicly excoriated the American president for leading him down a primrose path.

With nothing left for him to do, a frustrated Mitchell wisely decided to give up a foredoomed mission, leaving Obama to survey the wreckage of his own terribly flawed diplomacy.  It was Obama's hubris that did Mitchell in -- the president's chutzpah to believe that his personal intervention would succeed where previous presidents had struck out.