The folks at the Cook Political Report (subscription required) released their latest House race rankings late last week with the seeming timing of a document dump (sending out the ratings on the Thursday afternoon before a three-day weekend isn't exactly the way to draw attention), so some might have missed the news that of the 28 changes in race rankings, 27 represented upgrades in the prospects for the Democrats.

At present, Cook sees four seats as leaning towards a pick-up for the challenging party -- all four benefitting the Democrats. Among those races that Cook rates as either leaning towards a switch or a tossup, Republicans must defend 22 to the Democrats seven (or, in other words, Republicans are defending more than 75 percent of the most endangered House seats). Moving more broadly to the group of seats viewed as already competitive -- lean pick-ups, tossups, and lean retentions --  the Democrats must defend 19, the Republicans 33 (or about 63 percent). And in the even larger group of seats that are either competitive or potentially competitive, the GOP must defend a whopping 68 seats to the Democrats 33. That's right; Cook sees more than a third of the Republicans' 199 House seats potentially being in play in 2008.

The latest ratings from the Rothenberg Political Report aren't too dissimilar. Among the races that at best tilt towards the incumbent party but go as far as lean towards a switch, Rothenberg sees the Democrats playing defense in nine districts, the Republicans in 19. Overall, Rothenberg views 40 Republican seats in play and just 24 Democratic ones.

In short, the overall environment is beginning to catch up to the GOP in these race rankings. Although there has been a tendency to only look at the specifics of each individual race in divining that race's ranking -- a tactic, I might add, that was quite successful in cycles past in which there hasn't been much movement in either direction -- with the Democrats holding a sizable lead in the generic congressional ballot question and an unprecedentedly large lead in cash-on-hand among the congressional committees (the DCCC has $47.2 million in the bank to the NRCC's $6.7 million, a 7-to-1 advantage), there is little doubt that the outside forces coming to bear on the individual races now favor the Democrats (perhaps even enough so to sweep to victory some candidates who might otherwise not even have a chance at winning).