BOISE - Three Republicans and one Democrat on the 2011 redistricting commission voted Monday for two new U.S. congressional districts that shift the boundary between the Idaho's east and west, while still preserving the division of Ada County and Boise that's defined the state's political landscape for the last four decades.

Democrat Ron Beitelspacher, who joined Republicans Dolores Crow, Randy Hansen and Sheila Olsen in voting for the plan, said it wasn't his first choice.

Still, Beitelspacher said it was clear to him the GOP commissioners weren't going to change their minds, so he opted not to prolong debate any longer.

"I can count," he said, following the 4-2 vote. "It didn't appear to me there would be a change. If no votes are going to be changed, there wasn't a point to me sitting here wasting the people's money."

On Friday, this commission, the second of 2011 after the initial effort faltered, voted 6-0 for a 35-district legislative plan.

According to that proposal, 33 incumbents - most of them Republicans in GOP-dominated Idaho and many of them longtime lawmakers - will face each other during the 2012 round of elections, unless some of them voluntarily resign.

Population changes require Idaho to come up with new maps every 10 years, to preserve one-person, one-vote principles after the completion of the latest U.S. Census.

Friday's unanimous vote left only congressional boundaries to be hashed out, which the panel did in short order on Monday.

Currently, the border between Idaho's 1st Congressional District - now represented by Republican U.S. Rep. Raul Labrador - and the 2nd Congressional District - Republican Mike Simpson holds office here - carves up Ada County using Boise's Gary Lane and Cole Road, which run north and south, as the general dividing lines.

According to the new map approved early Monday afternoon, the line that separates eastern from western Idaho in Boise will follow landmarks including State Highway 55, the Boise River, Chinden Boulevard and Cloverdale Road to the south.

Notably, the small enclave of Garden City, nearly surrounded by Boise, falls in the 1st Congressional District, while the little foothills hamlet of Hidden Springs just northwest of Idaho's capital city is squarely in the second.

Shauneen Grange, a Democratic activist, and Elmer Martinez, a former Pocatello state representative, both voted against the plan that's now due to be presented to Secretary of State Ben Ysursa on Tuesday.

Grange and Martinez favored proposals that would have placed all of Ada County and Boise in the 2nd Congressional District, a move that could have brought Canyon County into the 2nd District, too.

That, however, would have displaced 400,000 of Idaho's 1.5 million people from the 1st Congressional District that also includes Idaho's northern panhandle to the 2nd Congressional District that encompasses places like Twin Falls, Pocatello and Idaho Falls.

Such a radical departure from the basic dividing line that's split Idaho's east from its west on a similar, if steadily westward-marching axis since the 1970s as the population of Boise grew was far too radical a change for Republicans Crow, Hansen and Olsen to stomach.

"Four-hundred thousand people would shift from one district to another," Hansen said following the vote. "It was too much for me."