I woke up this morning prepared to apply Jacobson & Kernell's Strategy and Choice in Congressional Elections to the OH 2 results, but discovered that Phil beat me to it. I'll just second his observation. OH 2 could loom especially large, since this year's high-profile contests probably won't play into any convenient spin for either side. Likely wins by "Whoopi Goldberg Republican" Mike Bloomberg and Wall Street Democrat Jon Corzine will mostly show that 2005 may be a better year for fabulously rich liberals than 2004 was for Soros, et al. If Democrat Tim Kaine wins the neck-and-neck Virgina governor's race, well he won Mark Warner's second term. If Republican Jerry Kilgore wins, a Republican has been elected governor of Virginia. Big whoop.
OH 2 also is the first "real world" impact of Bush's notably sagging poll numbers, both generally (the last few polls put his approval rating between 41 and 47 percent), and on Iraq (where only a little over 1/3 of the public approves of his performance). There's been a notable disconnect between Bush's increasing unpopularity in the country and his prowess within the Beltway. While Democrats already seem highly resistant to Bush on domestic issues, they may become more willing to challenge him on Iraq.
Bush's approval rating now resembles the average figures for the none-too-popular Jimmy Carter (46 percent) and Gerald Ford (47). Both of these presidents, however, experienced much smaller "approval gaps" than has Bush. (The "approval gap" is the difference in presidential approval between the two parties). Ford and Carter usually had approval gaps in the 30-point range. With the exception of the post-9/11 period, Bush has generally had approval gaps of over 60 points, often above 70.
Neither Ford or Carter ever had the kind of overwhelming support within their party that W has enjoyed, who has had the highest ratings ever found for a president among his fellow partisans (higher than Eisenhower or Reagan with Republicans or JFK with Democrats). Bush has usually had the support of over 90 percent of Republicans, while Ford and Carter rarely broke 70 percent among their partisans (and Carter sometimes fell below 50 percent). So even while Bush has struggled in the polls, he has not had to face the sort of turmoil within his party that these presidents endured.
On the other hand, Bush has had greater sustained unpopularity among opposite-party members of any president since Nixon during Watergate. Ford and Carter usually won the backing of at least 1/4 of the opposition, and often broke 30 percent. But for most of 2004 and 2005, Bush has been under 20 percent among Democrats (and not that much better among Independents).