Secondly, Obama wins most of the final primaries in North Carolina, Indiana, South Dakota, Montana, Guam, Puerto Rico and so forth.

Then, superdelegates, under pressure from Democratic Party chairman, Howard Dean, declare themselves publicly for their preferred candidate and Obama wins enough to put him over the top. Clinton then concedes. 

And finally, there is the possibility that Clinton wins or comes close in the next two states, and picks up enough superdelegates to come within striking distance of Obama's delegate lead.

She stays in the race all the way to the Democratic convention in Denver in August, and wages a huge floor fight to seat the disputed Florida and Michigan delegations.

This is perhaps Clinton's best chance of winning, but it would not be pretty.

Covering the race

Covering the Pennsylvania primary was fun. I enjoyed talking to people and political analysts in Philadelphia and elsewhere. The voters have a special sort of patriotic feeling for their home state and its institutions. And the cheese steaks and veal Siciliana were to die for.

On primary day, our superb Al Jazeera political coverage commando unit set up on the lawn in front of Independence Hall and did live shots for 13 hours.

There are many historic tourist attractions in the area and every American family with kids and every middle-school class trip seemed to have converged on the scene.

Many tourists came over totally befuddled as to what the television camera crews were doing pointing their cameras at Independence Hall.

We explained that we were doing reports about the primary and using the hall as a backdrop, but most people did not seem satisfied with that explanation.

They stood and squinted at the hall itself, as though expecting someone or something exciting to emerge from it.

Local curiosity

Media coverage hit overdrive for the Pennsylvania primary [AFP]