If you are curious about the accuracy of all the comparisons last night between Hillary Clinton's wins in PA and OH, check out Jay Cost's article in RealClearPolitics this morning. As he demonstrates in category after category, the two candidates performed roughly the same in the two states. If anything, PA's primary electorate turned out to be somewhat older, whiter, and more Catholic than OH's, which helped Clinton. Her margins among white woman and white men actually dropped a bit in PA, but they represented a slightly larger percentage of the vote than in OH.

Here's Cost's bottom-line take:

What we see, then, is what we have seen again and again in this contest. Clinton continues to do well with "downscale" whites. Obama does well with "upscale" whites and African Americans. What is intriguing about this result is not just that it is similar to Ohio - but also that it is similar after seven weeks and millions of dollars in campaign expenditures. Clearly, these voting groups are entrenched.

I'd add another factor: as Cost himself demonstrated during the last round of primaries, there's no real evidence that either candidate has enjoyed much of a "bounce" from winning any given contest, with the sole exception of Obama's Wisconsin victory, which seems to have been influenced by his Potomac Primary sweep. So if demographics are indeed destiny in this nominating contest, HRC's got an steep uphill climb in NC but a much better chance in IN. "Momentum," negative or positive, doesn't seem to matter to Democratic voters this year. But nor do gross ratings points of advertising bought. That's the bad and good news for HRC right now.