Nearly half the states are looking at a vigorous battle for control of their legislatures this year, with a power-flip hanging on turnover of just three seats or less.

This election marks the third straight in which power is held tenuously in so many places. Some see the situation as a symbol of the power of America's moderate middle — a group that's easily tipped one way or the other. It's led to more divided governments and a rise of the GOP, which for years ran behind the Democrats in most state capitols.

"To me it doesn't say anything about polarization," said Colorado Senate President John Andrews, where he rules the chamber with a scant 18-17 Republican majority. "It reminds us that politics are won and lost in the center. And that sure has been our experience in competing for Senate seats at election time and then crafting legislation here."

The Colorado Senate had long been in GOP hands until 2000, when Democrats took control. Republicans won it back in 2002; this year, both parties are working hard for victory, focused on a half-dozen competitive seats.

Similar struggles for legislative control are going on nationwide, such as:

— Tennessee, where Democrats control the Senate with a scant 18-15 majority.

— Oregon, where the Senate is evenly split 15-15.

— Washington state, where the Senate is 25-24 Republican and Democrats hold the House with only a six-seat majority.

There are other close fights in Indiana, Maine, North Carolina, New Mexico and more. Several places where the Legislature is up for grabs also are considered presidential battlegrounds.

Overall, 44 states hold legislative elections this year, with tough battles for control of 26 chambers in 23 states. In all, there are 5,804 legislative seats going to the voters.

Currently, Republicans control 21 state legislatures, Democrats control 17 and 11 are divided between the two parties. (Nebraska's unicameral legislature is officially bipartisan).

The last few elections have seen Republicans, who in 1990 controlled the entire legislature of only six states, gain significant strength. They made stunning gains in the GOP landslide of 1994, and in 2002 — for the first time in 50 years — actually controlled more seats than Democrats.

This is the election in which "Democrats need to discover if they've bottomed out," said Tim Storey, an elections analyst at the National Conference of State Legislatures. "Have Republicans maximized their gains?"

The legislative elections also add more fuel to the debate over the nation's political atmosphere. Is it polarized, with a deep, though narrow, divide? Or is it a debate about the center, with each party forced to the middle?

"If you listen to the political scientists, this polarization is real," Storey said. "The right question is, have we reached an era of shared power, of just heated, no-holds-barred battles for every legislative seat?"

Redistricting at the legislative level has had the same impact as redistricting at the congressional level, carving out huge numbers of safe seats that won't see much of an election battle at all, and a scant number of seats that will decide control.

Colorado's state GOP learned its lesson in 2000 and, going one step farther than the 72-hour get-out-the-vote effort championed by the national party, is operating a 96-hour sprint leading to Election Day, Andrews said.

"Losing hurts, but it sure was a wake-up call to our Republicans that we can't take elections for granted," he said. "(The campaigns are) already very active right now in midsummer, helping our six targeted Senate candidates walk precincts right now, doing literature drops, doing voter ID by telephone."

While legislative races are notoriously local, politicians from both parties say that the drive, money and organization from the presidential campaigns is bleeding over to help drive the statehouse races. And the excitement flows both ways.

"We've seen that energy carry into our assembly races," said Nevada state Assemblyman Bernie Anderson, a Democrat. "I've not seen that kind of desire to become involved in the political process, not ever. And I've been involved since the 1960s."