While the next slate of House elections does not occur until 2010, congressmen and their challengers certainly don’t take off the “off-year.” Instead, this year is a crucial one for the parties who must prove their recruiting chops, for the incumbents who seek big fundraising numbers and positive headlines, and for the challengers who have to prove their ability to take down a sitting member of Congress. And that doesn’t even include the open races, 18 so far, where incumbents have announced they will not seek re-election. In those districts, both parties are scrambling to find candidates who can quash takeover hopes or, conversely, take advantage of this rare opportunity.

Generally speaking, the president’s party loses seats in midterm elections. The actions of the president, even more than that of the Congress itself, shape the mood of the electorate and can help determine the magnitude of this legislative loss. The other main determinant of the potential for losses and gains is the national playing field. After picking up a net total of 54 House seats in the past four years, Democrats will be defending a lot of Republican Red turf. All told, 49 Democratic House members sit in districts which voted for Republican presidential candidate John McCain last November, while only 34 Republican congressmen sit in districts won by President Obama. Given the magnitude of Obama’s victory, these numbers understate the problem Democrats face, since some normally Republican districts were swept along in the Obama tide, but will likely return to their GOP roots in 2010.

Where, then, does each party stand? Republicans are rightfully optimistic in predicting gains in the House, since Democrats will be forced to play more defense than offense. However, that optimism should be tempered by Obama’s approval ratings, which have fallen, but still remain in the 50 percent range according to recent polls. If even these modest ratings continue for the Democratic president, it is hard to imagine a GOP landslide occurring at 2006 or 2008 levels, when Democrats capitalized on the unpopularity of Republican President George W. Bush, whose approval ratings were hovering a full 20 points lower than Obama’s. This lukewarm presidential approval, however, does create a set of conditions in which Republicans can certainly pick off a few incumbents while winning a number of open seat contests.

The GOP has also been drawing rave reviews for its candidate recruitment, fielding A-list challengers against many of the most endangered Democratic incumbents. They have also attracted quality candidates to oppose some normally safe representatives, a strategy the Democrats used to great success in 2006 and 2008. Open seats are another bright spot for Republicans, who have roughly equaled the number of retiring Democrats, in marked contrast to 2008, when 29 Republican congressmen gave up their seats compared to only six Democrats. A party also enhances its chances of electoral success simply by keeping its incumbents on the ballot.

Of course, some major hedging is due, as candidates will jump in and drop out over the next 14 months, scandals will develop and the national political climate will change somewhat. The bottom line?

After examining all 435 House races for 2010, the Crystal Ball projects that Republicans will gain between 20 and 30 seats. While this is nothing to sneeze at, especially given that it would be the largest gain for congressional Republicans since 1994, it still puts them short of the 40 seat pick-up they need to take back the House.

In total, 70 Democratic-held seats are competitive, while only 34 Republican seats are as endangered. A summary of all competitive races appears below. Bear in mind that races will be added to our competitive categories as new candidates jump in and incumbents jump out of each race over the next few months. Politics, like life, is full of changes and nobody can now predict what tomorrow will bring.