Well, it's Friday, and I guess a memo went out to all media "channels" that it is tired political sports metaphor day.  So, in the spirit of T.P.S.M.D. here goes:
It seems that backs are against the wall -- http://firstread.msnbc.msn.com/archive/2008/05/02/971485.aspx
Of course, from a sporting metaphor sense, given that Obama is marginally in the lead, and we are not yet in sudden death overtime, isn't it more accurate to say he is desperately struggling to protect his lead while fending off a desperate opponent?
Then of course there is the big game comparison --
http://www.cbsnews.com/stories/2008/05/02/opinion/main4064934.shtml
Cuz you see, Hillary is the scrappy N.C. State, a land grant college formed after the civil war, and Obama is the privileged and elitist UNC. Got that?  But just for "shits and giggles" carry on past the Nation Reviews article ending metaphor about how the Tar Heels did this season and check out the description of UNC's season here --
http://sports.yahoo.com/ncaab/teams/nat
"North Carolina State Team Report Apr 8, 2008

North Carolina State's potential dream season turned into a nightmare."

[Hey, don't slam ME as an Obamabot, its the National Reviews freakin' metaphor not mine]

Of course, what ESPN round up of "best of metaphors" would be complete without visiting --

http://talkingpointsmemo.com/archives/192685.php

GOT that?

Hillary by keeping it close will send a message that the fans should stay for sudden death overtime, even if the scoreboard says otherwise when the clock runs out.

Because of course --

http://abcnews.go.com/Nightline/Vote2008/story?id=4763893&page=1

You see? She would ALREADY be the Republican nominee...

Of course that's a little like a Canadian Football League Quarterback laying down on the 2 yard line and refusing to move because, "If this were the NFL, I'd already HAVE a touch down."

Except of course, this is more like that OTHER "football" (the one that focuses on kicking a ball with your foot), where cards are handed out for penalties, and the game keeps going until a referee mysteriously says "Its over!" (injury time and all that...)