Though these particular polls tell us little about what's going to happen in the remaining Democratic primaries, it's notable that a recent string of national surveys show Obama holding a statistically significant lead over Clinton.

A Pew poll released on March 27 had Obama ahead by 10 points: 49 percent to Clinton's 39 percent.

Over the next two days -- March 28 and 29 -- Gallup's tracking poll found Obama with an eight-point and seven-point lead, respectively.

Then yesterday, Obama's lead in the Gallup poll bumped up to 10 points. Today, it settled back in at eight points.

Here's a chart showing the Gallup trend lines over the past three weeks or so:

Meanwhile, Rassmussen's daily tracking poll has also been finding steady leads for Obama over the past few days -- though not the statistically significant advantages logged by Gallup and Pew.