QUANTIFYING THE ENTHUSIASM GAP, CONT’D…. Reader J.B. reminded me last night of an item from July about the “enthusiasm gap” that remains relevant. As is obvious by now, Republican voters are chomping at the bit, counting the days until the midterms, while Democratic voters are feeling listless and uninspired.

But two months ago, the Pew Research Center found that part of the problem was that rank-and-file Dems just weren’t aware of the impending threat. Less than a fifth of self-identified Democratic voters (18%) expected 2010 to be a worse-than-usual year for their party’s candidates. About half (48%) thought this year would be about the same, while 29% of Dems, apparently living in some kind of fantasy world, actually thought the Democratic majorities are likely to get bigger this year.

So, in case there are still some doubts among grassroots Dems, let’s make this really clear.

Among all registered voters … both parties are tied on the generic ballot, 43 percent to 43 percent, suggesting that Democrats could potentially blunt GOP gains in November with high turnout at the polls.

But right now, according to the poll, the interest level in the midterms is down among Democrats, African-Americans and younger Americans compared to 2006, when the Democratic Party won control of both the House and Senate.

If Democrats lose control of Congress, Hart argues, it’s “because they didn’t vote.”

The CNN poll shows Republicans with a narrow lead among registered voters, but a big lead among likely voters. The ABC poll shows the same thing — a 2-point GOP lead among registered voters becomes a 13-point lead among likely voters. The NBC poll shows the parties tied among all voters, but Dems trailing by nine among likely voters.

The enthusiasm gap, then, is likely the difference between a majority and a minority. I can only wonder how many Democrats will wake the day after Election Day with a feeling of deep regret.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.