As we await some post-convention polling in New Hampshire later this month, let's keep in mind two numbers going forward: 46 and 53.

Fifty-three is Jeanne Shaheen's pre-convention standing in the polls, according to Pollster.com.

That number is likely very close to the ceiling, the peak vote a Democrat could expect to get in a statewide election versus a competitive Republican.

And 46 is where Obama sits in a race that widened early in the summer and then narrowed.

Forty-six percent, as it happens, is a decent estimate of the floor for a competitive statewide Democratic candidate, running against a competitive Republican.

The question for Shaheen is, "Can she hold?" It's certainly an important question, but it's a different sort of question than we were asking six years ago.

Back in 2002, the question was: "Can a three-time moderate Democratic governor defeat a well-known Republican in a Republican state?"

The question for Obama will be, "Can he close this time?" And the voters with the answer to that question may well be those Shaheen voters who have not yet committed themselves to voting for Obama.

They're the difference between 46 and 53.

Dante Scala teaches American politics at the University of New Hampshire and blogs at Graniteprof.