

Sen. John McCain (R-Ariz.), right, and former Republican senator from Massachusetts Scott Brown arrive on stage for a town hall meeting Aug. 18 in Derry, N.H. (AP Photo/Jim Cole)

A new CNN/Opinion Research poll shows Sen. Jeanne Shaheen (D-N.H.) locked in a 48-48 tie with former senator from Massachusetts Scott Brown (R) -- a result that, if accurate, would elevate the U.S. Senate race in New Hampshire to a toss-up and significantly recast the battle for control of that chamber.

But regardless of the poll's accuracy (it's the first since January to show Brown tied, and he once trailed by double digits) there are some very interesting and telling numbers buried within.

Take a look at Shaheen's and Brown's personal image numbers.

Shaheen: 54 percent favorable, 42 percent unfavorable

Brown: 46 percent favorable, 48 percent unfavorable

That's right, a challenger whose personal image numbers are underwater is tied with an incumbent who is 12 points in the positive.

But really, this is nothing new. Brown has been semi-competitive with Shaheen for months in spite of this contrast. A WMUR-TV/Granite State poll from back in April showed Brown lurking within six points, despite his image being 10 points underwater (29-39) and hers being 14 points positive (49-35). And a poll conducted this month for the Democratic Senatorial Campaign Committee showed a similar phenomenon.

In fact, Brown has been underwater in virtually every major poll of this race, while Shaheen remains more popular than most senators being seriously targeted this year. And, actually, in this day and age, a 54/42 split would be the envy of many U.S. senators -- vulnerable or not.

Despite it all, it appears increasingly possible this will be a competitive race.

If you're Brown's campaign, you've got to think that demonstrates plenty of room for growth and suggests a very favorable environment in what is normally a swing state. President Obama's approval rating is just 38 percent -- lower than the nation as a whole -- so there might be something to that.

But if you're Shaheen's campaign, you've got to wonder how you could possibly lose when your candidate is significantly more popular and the other guy is consistently underwater. Are there really going to be a significant number of voters who dislike Brown, like Shaheen and still pull the lever for the Republican?

That would be fascinating.