Nationally, political analysts are closely watching the Congressional redistricting process, which will help determine the electoral battlefield for the next decade. Attracting less attention nationally -- but intense interest locally -- are line-drawing efforts that will reshape state legislatures.
Broadly, the redistricting maps that will take effect for the 2012 elections aren't expected to make sweeping differences in the partisan balance of legislative control nationally. The reason is that large reversals, like those that benefited the Republicans in 2010, often bring the winning party closer to the limits of their dominance. When a winning party draws lines in a bid to add even more seats, it can dilute district-by-district strength and make it possible for the party to actually lose ground.
So while 2012's new maps will have a limited impact on the balance of partisan control in state houses and senates, there are a few exceptions:
States where Republicans are expecting to see gains:
For generations, the legislatures of Alabama, North Carolina and Louisiana were controlled by Democrats. But over the years, the Party's popularity steadily eroded, enabling Republicans to take over both chambers last year in each of these three states.
The one-two punch of election victories and the opportunity to draw new lines probably seals GOP control for the long term in Alabama and Louisiana. These two states have a vibrant bench of Republicans that are replacing incumbent Democrats who may have been the last members of their party with a competitive chance to win those seats.
Still, additional GOP gains in these states may be numerically modest. During the 2010 election cycle in Alabama, "the GOP won virtually all the marginal or toss-up seats," says Jess Brown, a political scientist at Athens State University in Athens, Ala. "They may be able to solidify their incumbents, but it may prove difficult to actually enhance the number of GOP seats as a result of reapportionment."
As for Louisiana, which is known for its history of loose partisan loyalty, Republicans could pick up as many as 10 additional seats in the House and three to five in the Senate, which would be "enough to solidify their current majority and make it very hard for Democrats" to mount a comeback, says Pearson Cross, a political scientist at the University of Louisiana-Lafayette.
Post-redistricting, North Carolina's chambers may end up being somewhat more competitive than Alabama or Louisiana, since there's a bit more balance between the parties statewide. Still, the remapping process is allowing the GOP to shore up its new majorities in the Tarheel State. If the Republican-drawn maps withstand legal scrutiny, the GOP could have 27 or 28 reliably Republican seats in the 50-seat Senate, says Mark Binker, a state political reporter with the Greensboro, N.C., News & Record. The outcome in the House is less predictable since the Republicans' House map is more aggressive and thus has more marginally winnable districts for the GOP.
Wisconsin Republicans -- who took over both chambers of the Legislature in 2010 and proceeded to pass an aggressively conservative agenda -- had a free hand in drawing the new legislative maps this year. The maps should help the GOP protect their new majorities in the Assembly.
Meanwhile, the GOP is optimistic about its ability to modestly extend its newly acquired lead in the Indiana House, which has been narrowly divided for years. "Indiana's new maps were drawn specifically to make it almost impossible for the Democrats to get control of the lower house," said Brian Vargus, a political scientist at Indiana University-Purdue University Indianapolis.
In Alaska, redistricting by a GOP-leaning commission is expected to give a boost to more conservatives. This could help the GOP overturn an unusual bipartisan coalition that runs the evenly divided state Senate. Currently, the Senate Bipartisan Working Group includes 10 Democrats and 6 Republicans, with the four remaining Republicans in the minority.
An intriguing state is Virginia, where the parties passed a largely status quo plan, aiding the Republican majority in the state House and the Democratic majority in the state Senate. But Republican Gov. Bob McDonnell is popular, and the Senate will be under attack in the state's legislative elections later this fall.
States where Democrats are expecting to see gains
Ten years ago, Democrats and Republicans in California hammered out a bipartisan map that extended Democratic control of the Legislature, but prevented them from securing a two-thirds supermajority.
Now, a voter-enacted redistricting commission, which is comprised of 14 members split between Democrats, Republicans and "decline to state" voters, is charged with redrawing the lines. "A radical realignment of districts and incumbents will take place for both parties," says Tom Hofeller, a Republican redistricting expert.
Some Democrats predict that the new lines will allow their party to pick up a two-thirds majority in the state Senate, which would allow the party the support it needs to pass its tax and budget agenda. Democrats in the Assembly are less assured of securing the magic two-thirds majority.
A wild card for both chambers is the state's unusual "top two" primaries. These primaries can result in two Democrats or two Republicans facing off in the general election.
Florida voters will also influence their state legislative redistricting process. Last year, Floridians easily passed a ballot measure that imposed vague but mandatory criteria for partisan fairness when line drawing. The measure passed on a heavily Republican election day and despite the fact that it might tie the hands of GOP lawmakers seeking to protect their party's legislative advantage.
The GOP's state legislative margins are disproportionately strong. Curbing GOP lawmakers' line-drawing authority boosts Democratic chances of gaining ground in the legislature. "There should be major changes in state House and Senate seats, assuming the amendment is properly implemented," says University of South Florida political scientist Steve Tauber.
Elsewhere, Illinois Democrats -- already in control of both chambers -- are expected to post modest gains, one decade after redistricting efforts deadlocked and a plan was selected by drawing lots. Democrats in Delaware also should be able to shore up their gains in the state House, which had been controlled by the GOP for most of the past decade.
States where redistricting impacts are up in the air
A Colorado redistricting commission with a slight Democratic lean is poised to enact a map that keeps the state Senate in Democratic hands, but potentially increase the GOP's narrow edge in the state House. That margin is small and unpredictable, observers say.
In Iowa -- where the lines are proposed by a non-partisan legislative office, then voted on by lawmakers -- the state House should remain safely in Republican hands. However, the state Senate - now narrowly held by Democrats - should be in play. In the Senate, the new lines will pit 14 incumbents against each other, which will result in more Republican vs. Republican than Democrat vs. Democrat matchups.
In Arizona, where the GOP controls both chambers, Republicans are challenging Colleen C. Mathis, the independent chair of the state's bipartisan redistricting commission, alleging that she failed to disclose that her husband has ties to the Democratic Party. Given several layers of uncertainty about the process, it's too soon to tell what impact new maps could ultimately have.
In Nevada -- where the Democrats control both chambers and legislative redistricting has already led to court challenges -- the closely divided state Senate will probably remain competitive under almost any scenario. The state Assembly will likely see GOP gains. If the maps are drawn based on geographical and population factors alone and without regard to incumbency, Republicans in the Assembly would probably gain about three to five seats. Only on the high end of that scale would the GOP be able to take control of the chamber.
In Minnesota, the GOP seized both legislative chambers in 2010, gaining a sizable number of seats. Because of this, Republicans have the most to lose in redistricting. A divisive government shutdown "could be a problem for GOP incumbents," says Carleton College political scientist Steven Schier. "We could easily see a 10-seat swing out of 67 in the state Senate and a 20-seat swing out of 134 in the state House."
Still, Tim Storey, a redistricting expert at the National Conference of State Legislatures, urges caution when extrapolating potential gains from new lines.
"A good map can give a party's candidates a head start, but elections are notoriously unpredictable. National and top-of-the-ticket forces will play a big part," Storey says. "Plus, it still matters whether you run good candidates and whether they run smart or dumb campaigns."