Everyone knows that the South could be the lynchpin region this election season, with control of the Senate hinging on races in Tennessee and Virginia, and at least seven House races in the South among the most bitterly contested in the country.

But here's another reason to keep an eye on the South, specifically Tennessee: it's one of 11 states where control of the state legislature will be decided this November.

As the New York Times reports today, 6,000 legislative seats are up for grabs in 46 states this year. Republicans control both chambers in 20 states; the Democrats, in 19 states.

The states to watch in 2006: Indiana, Iowa, Michigan, Minnesota, Nevada, Oregon, Pennsylvania, Tennessee and Wisconsin, where Republicans have narrow majorities in the lower house or senate. Democrats have narrow majorities in Colorado, Maine and Montana.

The Times notes that -- contrary to the notion of "red states" or "blue states" -- most state legislatures are bitterly contested territory:

What makes the races even more suspenseful is that the parties have not been so even in decades, if ever. Of the 7,382 statehouse legislative seats across the country, Democrats hold 21 more than the Republicans, a margin of less than half a percent.

In 17 of the 46 states that will elect some or all of their state senators, a shift of only three seats would alter party control in the senate, according to the National Conference of State Legislatures. In 12 state houses, a shift of five or fewer seats would tip the balance.

The political parties realize the importance of these battles:

The Democratic Legislative Campaign Committee plans to spend $9 million to $10 million on legislative races, up from $6 million to $7 million in 2004. Its counterpart, the Republican State Leadership Committee, has nearly doubled spending on state races, including for legislators, to $20 million.

This is what makes the work of groups like the Progressive States Network so important.

UPDATE: Stateline notes that two other Southern states, Kentucky and North Carolina, have slim Democratic majorities in their state legislatures, which will be contested next week.