Democrats may be headed for a double whammy at the polls next month.

Besides significant losses in the 2010 midterm elections, results in key states could make it harder for them to recover in the 2012 congressional contests.

That's because projected Republican gubernatorial and legislative gains could enable the GOP to create more favorable U.S. House districts in many states where the census will require changes.

The Democrats already face an uphill fight two years from now to defend some U.S. Senate seats they narrowly won in 2006. So even if President Barack Obama wins a second term, he could easily face an unfriendly Congress dominated by political opponents.

The shape of the 2012 Senate map stems from the Democrats' 2006 successes. As a result, Republicans hold only 10 of the 33 seats now scheduled to be contested, including Sen. Kay Bailey Hutchison's Texas seat.

Today, few of those 10 appear vulnerable to Democratic takeover. But the dynamics in several, including Texas, could change with Republican primary challenges from the conservative tea party groups that defeated several GOP establishment candidates this year.

By contrast, several Democratic incumbents could face stiff fights, including Sens. James Webb of Virginia, Ben Nelson of Nebraska and Jon Tester of Montana.

But the biggest fallout from anticipated 2010 Republican successes could be in the House, damaging Democratic chances of regaining seats they lose this year, even if the economy picks up and Obama mounts a successful re-election campaign.

That's because those expected gains will coincide with the 2010 census, requiring the redrawing of legislative and congressional districts to meet population changes.

"The timing for a swing-back election could not be worse, assuming this is a good election for Republicans nationally," said Matt Angle, a Texas Democratic strategist. "It will allow them to use the redistricting process to inflict damage that could last for 10 years."

Final census figures won't be released until later this year, but estimates have Southern and Western states gaining 12 House seats, including four in Texas and two in Florida. Northeastern and Midwestern states would lose a like number, including two each in New York and Ohio.

Electing more Republican governors and state legislators could enable that party to control redistricting in many states and maximize Republican members of Congress.

In similar circumstances a decade ago, the GOP added multiple seats in states like Michigan and Pennsylvania, which lost seats overall, and Texas and Florida, which gained them. This would be a third consecutive decade in which Republicans benefited from census-induced reapportionment.

The poster child for the GOP's post-2000 redistricting success, of course, was Texas. Under the leadership of former House Majority Leader Tom DeLay, it switched the state's House delegation from 17-15 Democratic to 21-11 Republican and eliminated five Democratic members.

This time, because much of Texas' population growth has been Hispanic, there has been talk of adding two Hispanic majority seats likely to be Democratic and two white majority seats likely to be Republican.

But Democrat Chet Edwards' Central Texas seat may well go Republican this year. Some Republicans believe they could gain another seat by the way they redraw districts, because the Democratic drive to impact redistricting by retaking the Texas House seems likely to fall short.

Another potentially significant national factor is California's vote on two ballot issues that could assign redistricting to an independent commission, rather than the Democratic-controlled legislature. While a significant issue will be accommodating California's burgeoning Hispanic population, a non-partisan solution could reduce the current 34-19 Democratic majority.

The headlines on Election Day almost certainly will focus on Congress and, secondarily, governorships. But the less-publicized battles for control of state legislatures could have the larger long-term impact.

Carl P. Leubsdorf is the former Washington bureau chief of the Dallas Morning News.