Yesterday I referenced the Gallup survey showing that Republicans lead by 51 percent to 41 percent among registered voters in Gallup’s weekly tracking of 2010 congressional voting preferences. The poll is getting a lot of attention, and rightfully so. Frank Newport, editor in chief of Gallup, put the results in context:

The Republican leads of 6, 7, and 10 points this month are all higher than any previous midterm Republican advantage in Gallup’s history of tracking the generic ballot, which dates to 1942. Prior to this year, the highest such gap was five points, measured in June 2002 and July 1994. Elections in both of these years resulted in significant Republican gains in House seats.

As a further reference point: in August 1994, Republicans and Democrats were tied in Gallup’s generic ballot (46/46). And in the final pre-election poll in 1994, when asked if the elections for Congress were held today which party’s candidate (Republican or Democrat) would you vote for in your congressional district, the public preferred the Democratic candidate by a two-point margin (43 v. 41).

The GOP gained 54 seats in the House.

(A caveat: the data do not appear to have Gallup’s likely-voter screen applied to them, a practice the organization now employs starting in October. Data of national adults, rather than likely voters, usually will add several points more to Democratic candidates.)

Now, the generic ballot question, though significant, is not dispositive. The problem for Democrats is that almost across the board, the polling news is awful. President Obama is witnessing a hemorrhaging of support from among independent voters. And the enthusiasm gap, which favors the GOP by 20-25 points, is also an ominous sign for Democrats.

“The intensity gap is the biggest I’ve seen in 30 years,” the Republican pollster Bill McInturff told Bloomberg News’s Al Hunt. “This is going to be a massive election like 1974, except it will happen to the Democrats this time,” according to McInturff. In 1974 Democrats, in the aftermath of the Watergate scandal (Nixon resigned in August), took 49 seats from the Republican Party and increased their majority above the two-thirds mark (from 242 to 291).

“Today,” proclaimed the Democratic strategist James Carville in the wake of 2008 Obama’s victory, “a Democratic majority is emerging, and it’s my hypothesis, one I share with a great many others, that this majority will guarantee the Democrats remain in power for the next 40 years.”

It looks like Carville’s Democratic majority may fall around 38 years short of his prediction.