Jonathan Last at Philly.com:
Lost in the excitement of Barack Obama's coronation this week was an inconvenient fact of Tuesday's results: Hillary Clinton netted approximately 150,000 votes and is now poised to finish the primary season as the popular-vote leader. In some quaint circles, presumably, these things still matter....To understand how razor-thin this majority is, consider that if the Puerto Rico turnout is slightly larger than we have imagined - or Clinton's margin is slightly greater - then Clinton would finish the primary process leading in every conceivable vote count. With two million voters, a 28 percent victory would put Clinton over the top even in the count, which excludes Florida and Michigan and includes estimates for Obama's caucus victories.
It is this looming prospect which explains the tremendous pressure Obama partisans and the media are putting on Clinton to drop out of the race. They want her gone now because they understand that she has an excellent chance of finishing as the undisputed people's choice.