The consistent partisan outcome in California House races that lasted for decades wasn't an accident.
In 2001, the state's House delegation — the Democrats and Republicans serving in Congress — brokered an agreement to draw boundaries that would protect their existing partisan split, recalled Tom Davis, a former Virginia representative who led the National Republican Congressional Committee in the 2000 and 2002 elections.
Davis said he "jumped" at the chance to reach such a deal. "Democrats controlled everything" in the state legislature, he said. "And with Democrats drawing the lines, they could have drawn us down to 15 seats pretty quick."
The split of 33 Democrats and 20 Republicans envisioned under the plan played out in the 2002 election and again in the 2004 vote. After Democrats won the one seat from Republicans in 2006 to alter the delegation's makeup to 34-19, that breakdown was replicated in the 2008 and 2010 elections.
In 2008, California voters formed their commission with the backing of Charles Munger Jr. the son of Berkshire Hathaway Inc.'s vice chairman, and Schwarzenegger. Its initial charge was to draw state legislative districts. Voters in 2010 expanded its scope to include congressional districts.
In the 2012 election, the first held based on the commission-drawn map, Democrats won 38 seats while Republicans took 15.
The commission is made up of five Democrats, five Republicans and four independents. The members can't be lawmakers, public officials, legislative aides or lobbyists.
When the commission completed its work, the congressional districts were more manageable in size and shape and emphasized cohesion on some matters, such as bunching urban or rural voters together. The map also created a few competitive seats, although a majority still carried a partisan advantage.
In the 2012 presidential race, Obama or Republican nominee Mitt Romney won by more than 10 percentage points in all but seven of California's redrawn 53 House districts, according to data compiled by Bloomberg News. In three of the districts, a majority of voters supported the presidential candidate from the party opposite to the congressional candidate who won.