Starting in 2013, one party will hold both the legislature and governorship in 37 states. At the same time, an additional seven states will have new legislative supermajorities -- the threshold at which the legislature can override a gubernatorial veto or pass certain types of legislation that require more than a simple majority.

These results suggest a shift toward more aggressive partisan politics, as minority parties find themselves almost powerless to check the policy impulses of the majority. But a closer look suggests a more nuanced, even modest impact.

To be sure, the topline numbers are striking. According to the National Conference of State Legislatures (NCSL), one party will control both chambers of the legislature in at least 43 states. Of these, 26 have unified Republican legislative control, while 18 have unified Democratic control.

By contrast, just three states -- Iowa, Kentucky and New Hampshire -- will have a clear split in party control in 2013. (One state, Nebraska, has a unicameral, nonpartisan Legislature, while three states -Virginia, New York and Washington state-each have one legislative chamber with partisan control that is hard to characterize.

The last time there was such a small number of divided chambers was way back in 1944, according to NCSL. And if you factor in governorships, the degree of one-party control nationwide in 2013 will also be high by historical standards. Twenty-three states will have unified Republican governance in 2013, up from 18 before the 2012 election, while 13 states will have unified Democratic governance, up from 11. All told, that leaves only about a dozen states where the minority will have any toehold in state government -- eight fewer states than previously.

In 2013, the only states with any clear division of control will be Arkansas, Iowa, Kentucky, Maine, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York and Rhode Island. (This is the smallest number of states with divided government since 1952, when there were eight, according to NCSL. States with divided government peaked at 31 in 1988 and 1996, and has declined precipitously since 2004.

Meanwhile, legislative supermajorities are also on the rise. NCSL found that "fully half the country is poised for a veto-proof legislature in 2013." Heading into the elections, 22 states were veto-proof; the net number for 2013 is 25. That's the highest level in at least a decade, according to NCSL. The states with new supermajorities for 2013 are California, Georgia, Illinois, Missouri, North Carolina, Ohio and Oklahoma.

It would be easy to view these trends as advancing the cause of ideological polarization and hard-line partisan agendas, and it's true that partisan warfare hardly seems in retreat these days. There is something to the idea that red states and blue states are becoming increasingly polarized. Still, the 2012 election results may not be the sharp turning point that one might expect. Here's why:

The trend isn't exactly new

Lots of legislatures already had the capability to override their governor in 2010. A dozen states had supermajority overrides in 2010, and six others (Alabama, Arkansas, Indiana, Pennsylvania, Tennessee and West Virginia) could override the governor with a simple majority, at least on certain types of votes. (For a rundown of how veto overrides work in each state, see here for governors and here for state legislatures.)

The states where these changes are occurring don't seem poised to initiate explosive ideological conflict

In most of the states where one party has increased its control, the shift won't be at odds with the states' prevailing partisan trends. Despite a rise in the number of veto-proof legislatures, relatively few of the recent shifts have occurred in states where the governor hails from the opposite party -- the scenario in which a legislative supermajority possesses the greatest ability to flex its muscles.

In 2013, only three states will have a legislative supermajority for one party but a governor of the opposite party -- Arkansas, Missouri and Rhode Island. By contrast, of the 14 veto-proof legislatures in 2003, half were in states with divided governments, according to NCSL.

In Arkansas, the Legislature can override the governor with a simple majority, so the Democrats had the power before the GOP took over both chambers in the 2012 election. In both Arkansas and neighboring Missouri, a conservative legislature will be coexisting with a moderate-to-conservative Democratic governor, reducing the likelihood of sharp ideological clashes. And in Rhode Island, the Democratic supermajority will be working with an Independent governor, Lincoln Chafee, who's flirting with the possibility of running for a second term as a Democrat.

For the most part, today's legislative supermajorities are operating in states with a governor of the same party. For the Democrats, these include such solidly blue states as Delaware, Hawaii, Maryland, Massachusetts and Vermont. For the GOP, these include such states as Georgia, Idaho, North Dakota, Oklahoma, South Dakota, Utah and Wyoming. While such large majorities can produce divisions within the majority party, battles between the two parties are highly unlikely.

One state that could have had seen a volatile partisan divide in 2013 was North Carolina. In 2011 and 2012, a new, but fairly narrow Republican legislative majority coexisted with a Democratic governor -- a lineup that led to bitter clashes on a number of policy fronts. But in the 2012 elections, the GOP achieved a legislative supermajority and took over the governorship.

"With the election of Pat McCrory as governor -- the first Republican governor in North Carolina in 20 years -- the meaning of the GOP achieving the supermajority in both chambers changed," said Jonathan Kappler, research director of the North Carolina Free Enterprise Foundation. "GOP leaders in the House and Senate will no longer be pushing against a Democratic governor and looking for Democratic votes to overcome potential gubernatorial vetoes."

Meanwhile, in 30 of the 37 states with unified partisan control, the party in control is the same as the party that won the presidential contest in that state in 2012. In other words, in more than 80 percent of these unified-control states, the party in power at the state level is broadly in tune with how voters feel about national politics.

Sometimes unified governments and supermajorities aren't all they're cracked up to be

Take Oklahoma. There aren't too many liberal Democrats left in Oklahoma, but there were enough in 2011 to strike an unlikely alliance with Tea Party Republicans to deny the establishment wing of the state GOP a supermajority on some key issues -- something that dashed heightened expectations for the state's dominant party, said Oklahoma-based political scientist Rick Farmer, a fellow at the Ray C. Bliss Institute of Politics at the University of Akron.

Or consider California. As a result of the 2012 elections, Democratic Gov. Jerry Brown now has a Democratic supermajority in both legislative chambers -- an especially important threshold in California since fiscal changes require a two-thirds majority. The new two-thirds Democratic threshold, however, will not necessarily be a panacea for Brown, said A. G. Block, program director at the University of California Center Sacramento. "There is a difference between a supermajority and a 'functioning supermajority,'" he said. "A functioning supermajority is one where leadership can count on 54 votes in the Assembly and 27 in the Senate on every key issue. I'm not sure that's possible, especially in the Assembly, where 38 new members were sworn in on Dec. 5. Many of those Democrats were elected in competitive districts. I think it is unlikely that Democrats will be able to ram through new spending programs where some of their supermajority members might have to cast votes that cost them politically in 2014."

Sometimes, a governor who's trying to steer a middle course would rather have the opposite party in charge of at least one chamber. For instance, in Colorado, moderate Democratic Gov. John Hickenlooper will have to take a new approach to the Legislature, which will now be entirely in Democratic hands. Hickenlooper, and other governors in his situation, will need to fend off proposals by the more hard-line elements of his own party rather than basking in an era of bipartisan cooperation. According to, Hickenlooper vetoed only two bills that emerged from the partially Republican-controlled Legislature, neither of them on hot-button issues.

For all these caveats, there should still be a number of states where the spread of supermajorities and unified government could cause some fireworks over the next two years. Here are some of them:

The dozen states with genuine divided government

An all-Republican legislature and a Democratic governor will face off in Arkansas, Missouri and Montana. Meanwhile, all-Democratic legislatures will be sparring with Republican governors in Nevada, New Mexico, New Jersey and Maine.

In each of these states, you can expect some heavy battling over policy priorities. Raising the stakes, the GOP governors in Nevada (Brian Sandoval), New Mexico (Susana Martinez) and New Jersey (Chris Christie) are considered rising stars within their party, meaning the Democratic knives will be out.

Other states have one chamber held by the party that doesn't control the governorship; these states should also see some partisan sparring. They include Iowa, Kentucky and New Hampshire.

Six states where unified partisan control at the state level clashes with the 2012 presidential vote

There are seven states with gubernatorial and legislative control concentrated in one party yet where the opposite party won the presidential vote in 2012. They are Florida, Ohio, Michigan, Pennsylvania, Virginia, West Virginia and Wisconsin.

Set aside West Virginia, where the Democratic majority is solidly conservative. The remaining six states -- with the possible exception of Pennsylvania -- include some of the most hotly contested swing states in the presidential election, and all six were won by President Obama last fall.

The fact that these six Obama swing states have unified Republican control at the state level is a recipe for political combat. Republican governors and legislators have not been shy about pushing the policy envelope, particularly after Wisconsin Gov. Scott Walker won a recall vote by an even larger margin than his initial victory, despite signing a spate of highly contentious bills in the interim, including curbs on union rights.

In Pennsylvania, for instance, the GOP approved a voter ID law (later blocked by the courts) as well as major cuts to education and urban development and an industry-friendly approach toward natural gas fracking, said Muhlenberg College political scientist Christopher Borick.

And in Michigan, Republican Gov. Rick Snyder -- who for most of his first two years in office had been viewed as a pragmatist -- signed right-to-work legislation during a lame-duck session even though he had initially balked at doing so. This left unions and their Democratic allies up in arms.

In Michigan as in some of these other states, Democrats are licking their chops, saying that the GOP's staunchly conservative agenda is at odds with ordinary voters' leanings. And the Democrats may have a point. Governing has rated Florida's Rick Scott as vulnerable in 2014, while Michigan's Snyder, Ohio's John Kasich, Pennsylvania's Tom Corbett and the open seat in Virginia being vacated by Bob McDonnell are potentially vulnerable for 2013-2014. Aggressive Democratic challenges are expected in each case.

Still, none of these contests will be a slam dunk for the Democrats. In Michigan, "so much time remains between now and November 2014, and so much depends on the economy, that we'll just have to wait and see whether this means the GOP will 'pay a price' 22 months from now," said Bill Ballenger, publisher of Inside Michigan Politics.

The legislatures in these states will also be targets for the Democrats, but they may pose an even steeper challenge due to an effective redistricting effort by the newly installed GOP majorities after the 2010 Census.

While Democrats made incremental gains in several of these states in the 2012 elections, the more notable result may be that the GOP -- bolstered by the favorable district lines -- held on to each of the legislative chambers that were contested in these states in 2012. This means that Obama's victory had limited coattails in swing-state legislatures -- and if GOP control can survive a year like 2012, it might be able to survive longer than that.

Finally, there's one state that has both a newly empowered supermajority as well as unified government at the state level that conflicts with the state's 2012 presidential vote.

That would be Ohio. The Buckeye State was the most hotly contested battleground in the 2012 presidential election, and it should remain a focus of attention into the 2014 election cycle.

Republican Gov. John Kasich suffered a stinging rebuke in 2011 when voters overturned labor union curbs he and the Legislature had enacted. But his approval ratings seem to have turned a corner, even though the state backed Obama by an unexpectedly comfortable margin. "By November 2012, little of (the labor-initiated repeal) really resonated," said Doug Preisse, a GOP strategist in Columbus.

Will Kasich and the numerically enhanced Legislature now push a strong conservative agenda? Not necessarily. Kasich has indicated a reluctance to seek the kind of right-to-work legislation that Michigan's Snyder signed, and a stringent anti-abortion bill has languished. Observers expect an agenda that includes nuts-and-bolts issues such as taxes, education and bonding rather than hot-button topics.

The voters' rejection of the labor bill "was a hard lesson for the GOP, so I think they see the risk of reaching too far," said Bill Binning, a Youngstown State University political scientist and former GOP official. "Kasich will want the focus to be on creating jobs. Making Ohio job-friendly is a safe place to be in Ohio."