Politics isn't always a zero-sum game: Just because one side is down doesn't mean the other side gets to move up. So while President Obama's approval ratings have slipped since the summer, voter perception of the "out party" can still play a hand in determining control of Congress in 2010.

The most recent polling by CNN/Opinion Research Corp., Pew Research Center and Quinnipiac put disapproval ratings of congressional Republicans between 60 percent and 66 percent. Congressional Democrats aren't exactly beloved, but they are disliked a bit less. Their disapproval ratings ranged from 53 percent in the Pew poll to 59 percent in the CNN poll.

While no Democratic strategist I've talked to thinks their side won't lose seats next year, many contend that disenchantment with the Republican Party brand will insulate Democrats from a game-changing "wave election" such as those in 1994 or 2006. But GOP pollster Glen Bolger, when analyzing polling from Democratic strategic and polling group Democracy Corps, noted that "it's a lot easier for the GOP to fix our fading problems than it is for the Dems to fix their growing problems."

Even on issues where Democrats are traditionally strong, like health care and Medicare, Democratic candidates led by just 1 point and 3 points, respectively.

In response to Bolger's analysis, Democracy Corps noted that "one of the main factors that produced the wave elections of 1994, 2006 and 2008 was a significant favorability advantage for the out-of-power party that does not exist today. In fact, the continuing tarnish on the national Republican brand is perhaps the biggest hurdle to larger Republican gains in 2010."

Yet, midterm elections are a referendum on the party in power, not the folks in the minority. In 2006, Democratic House campaign chairman Rahm Emanuel was famous for telling his candidates that the election wasn't about them, it was about the GOP. Democrats didn't need to provide the "answers" to fixing the economy or the war in Iraq. Just not being Republicans was enough of a reason for voters to support them. When I asked GOP pollster and strategist Steve Lombardo what he thought about the "brand identity" problem for the GOP, he responded by saying that the issue "is not about 'fixing GOP favorability.' Brand identity is nice, but in this case it's less about the GOP brand identity than it is about the lousy brand identity of the Democrats."

It's also important to compare apples to apples. For example, how Americans feel about each party overall can be very different from how they perceive that party's representatives in Congress. For example, the CNN/Opinion Research poll showed Democrats with a 53 percent to 41 percent favorable to unfavorable rating. Yet, when asked to rate "the way Democratic leaders in Congress are handling their job," the disapproval rating was 18 points higher, at 59 percent.

If we use perceptions of party leaders in Congress as the benchmark, rather than perceptions of the party as a whole, we find that Democrats weren't all that popular in '06, even as they were poised to take control of Congress. In early October 2006, the Pew poll showed that 53 percent said they disapproved of the job Democrats in Congress were doing. Right before Democrats picked up 21 house seats in 2008, an October CNN poll gave Democratic leaders a 64 percent disapproval rating.

It'll be interesting to see if the end of the health care debate boosts the approval numbers of congressional Democrats and/or Republicans. After all, while the idea of "sunshine" on the legislative process sounds great, in reality it only helps to convince most Americans that the process itself is broken. The constant coverage provided by cable TV, which revels in conflict and minute-by-minute process stories, only makes the legislative process look more unsavory.

More important, as Bolger points out in his Democracy Corps poll analysis, Republicans are well-positioned on the issues. In the 40 "battleground" districts held by Democrats that were polled by Democracy Corps, voters thought Republicans would do a better job on the economy (4 points), government spending (10 points) and taxes (12 points). Even on issues where Democrats are traditionally strong, like health care and Medicare, Democratic candidates led by just 1 point and 3 points, respectively.

Of course, the problem with macroanalysis is that it ignores candidates and campaigns. To be sure, Democrats can still win in districts where the GOP is well-positioned for a pick-up (see N.Y.-20 and the New Jersey governor race). But it's also important to remember that love isn't the primary motivator in midterm elections -- anger is. So while Republicans are disliked today, they may look a lot more appealing next year if voters are frustrated by what Democrats in Washington have or haven't done.