Update: 6:14 p.m. Revised section on legislative district spat to reflect that Republican Tom Huff said he had no problem with a majority Latino legislative district - dispute was over the precise number and boundaries of district.

Update: 1:44 p.m. with news of impasse on Eastern Washington legislative districts, and a few more details on congressional map impacts

Washington's new 10th Congressional District will be anchored around Olympia under a deal announced by the state's bipartisan redistricting commission Wednesday.

The new district would be one of two open seats that could become swing districts in 2012 under the new maps, commissioners said.

The 1st Congressional District, being vacated by Democrat Jay Inslee as he runs for governor, will be split just about evenly between Republican and Democratic-leaning communities.

"It may easily be the most evenly divided congressional district in the United States of America," said former U.S. Sen. Slade Gorton, who negotiated the congressional maps with Democrat Tim Ceis, the former Seattle deputy mayor.

The new maps also would create the state's first majority-minority congressional district by pushing the 9th District, now represented by Democrat Adam Smith, north into south King County.

While the commission seemed largely at peace over the congressional maps, the issue of Latino representation in Eastern Washington threatened to derail the entire redistricting process on Wednesday.

After weeks of intense negotiations behind closed doors, an impasse between Democratic commissioner Dean Foster and Republican Tom Huff spilled into the panel's public meeting Wednesday afternoon.

The fight was over Hispanic representation in Eastern Washington legislative districts.

Foster's plan pushed for a strongly majority-Latino 15th Legislative district in the Yakima County area. Huff, the Republican, said his plan would be majority-minority, but not majority Latino.

Huff said he had no problem with a majority Latino district, but that Foster kept trying to move the numbers around.

Huff appeared caught off guard when Foster brought that disagreement out in the open, calling the maneuver "scripted" and unfair.

He noted that Democrats had been allowed to draw the legislative lines in the Seattle-area, and that the same should go for Republicans in Eastern Washington: It's pretty much Republican territory," Huff said.

But Democrats demanded to see data on how Huff's plan would divide Latino voters among multiple legislative districts.

On the Congressional side, besides creating two potential swing districts next year, the new proposed map would protect incumbents of both parties.

For example, Republican Dave Reichert's 8th District would grow more conservative under the plan. The 8th would lose part of its urban core and cross the mountains to encompass Chelan and Kittitas counties.

Democrat Rick Larsen's 2nd District, meanwhile, would cede the vast rural reaches of Whatcom, Skagit and Snohomish counties, becoming a more coastal, liberal district.

The proposed maps are not final yet. At least three of the four voting commissioners -- two Democrats and two Republicans -- must okay the new maps. The commission has until Dec. 31 to finish its work or the task falls to the state Supreme Court.

The Legislature will have a chance to tweak the maps in the upcoming session - but such changes require a two-thirds vote and can affect no more than 2 percent of a district's population. The governor has no veto power over the maps.