As we reported today, Washington's 2012 political landscape will include two open congressional seats -- but only one looks like a true swing district.

Using data from the 2010 Senate race, it appears that the state's new Olympia-centered 10th District starts off leaning Democratic. Voters in that district backed Democrat Patty Murray last year over Republican Dino Rossi 53%-47%. And that was during a Republican year. In 2008, the district backed President Obama over Republican John McCain by 58%-42%.

That's good news for Democratic candidate Denny Heck, who lost a congressional bid last year when Olympia was still part of the 3rd District. On the Republican side, Pierce County Councilmembers Dick Muri and Stan Flemming have indicated they're in the 10th District race.

The reshaped 1st District, however, looks like more of a genuine tossup. Voters living in the redrawn 1st went barely for Rossi over Murray: 51%-49% -- again, during a Republican year. In 2008, a Democratic wave year, the district backed Obama over McCain 57%-43% 53%-47%.

The current 1st District, by comparison, has been much more Democratic, backing Murray over Rossi 56%-44% in 2010. In 2008, Obama took 63 percent of the district's vote.

This data also confirms that the commission -- which is bipartisan, but not nonpartisan -- protected all the current congressional incumbents.

Democratic Congressman Rick Larsen nearly lost to Republican John Koster last year, but now has a redrawn 2nd District that is much more Democratic. In 2010, voters living in the revised 2nd District backed Murray 55%-45%, compared with just 51%-49% in the current 2nd District configuration.

And Koster, of course, has been moved into the new 1st District, leaving Larsen with no formidable GOP challenger.

On the Republican side, Rep. Dave Reichert's 8th District will lose its urban bits and become much more conservative, sweeping across the mountains all the way to Lake Chelan. Based on the 2010 Senate race data, the new 8th District went from nearly even to 55 percent Republican.

In fact, the new 8th District looks more likely to produce a challenge from the right to Reichert than any solid Democratic hopeful. Reichert has taken a lot of flak for his environmental votes from hard-core conservatives.

In the same way, do not be shocked if Rep. Adam Smith (D) faces a primary challenge from the left. Smith's redrawn 9th District has lost its Fort Lewis component and now will be the state's first majority-minority district (with 50.33 percent people of color.) There already have been rumors of some minority candidates considering a run.

Of course, all of this could change if the redistricting commission fails to meet its Jan 1 deadline for finishing its maps. In the last day, an impasse over Eastern Washington legislative districts has threatened to upend the whole deal.

By law, the commission must approve both the legislative and congressional maps as a set. They cannot be separated. If the commission does not pass new maps by Jan. 1, the task will fall to the state Supreme Court.

Below is a quick chart of how the new congressional districts stack up with the current ones, using the 2010 Senate race data. All numbers were crunched by Justin Mayo, the Times resident data whiz.