AUSTIN, Texas – A surge of Hispanic residents and other population gains have Texas poised to add more congressional clout than any other state, but a partisan fight now looms over exactly where the new seats should go.

Texas is gaining four seats in the U.S. House, twice as many as Florida, the only other state to pick up multiple ones, according to new population figures announced Tuesday by the U.S. Census Bureau. All told, Republican-leaning states will pick up at least a half-dozen House seats thanks to the 2010 census, which found the nation’s population growing more slowly than in past decades but still shifting to the South and West.

With Texas Republicans using recent elections to fortify their already solid control of the state Legislature, the political process of redrawing the state’s congressional map would seem to benefit the GOP, too.

But Democrats say not so fast.

Boyd Richie, chairman of the Texas Democratic Party, said Hispanic and black population growth account for the additional seats, and he vowed to fight for a redistricting plan that takes their numbers into account.

“A legal and fair redistricting process must produce new congressional districts that reflect the Hispanic and African American population growth,” Richie said. “Our Democratic numbers may be down, but we are not out. Democrats cannot and will not allow our voices to be silenced in this critical process.”

The Census Bureau said the nation’s population on April 1 was 308,745,538, up from 281.4 million a decade ago. The growth rate for the past decade was 9.7 percent, the lowest since the Great Depression.

The new numbers are a boon for Republicans, with Texas leading the way among GOP-leaning states that will gain House seats, mostly at the Rust Belt’s expense. Following each once-a-decade census, the nation must reapportion the House’s 435 districts to make them roughly equal in population, with each state getting at least one seat.

In all, the census figures show a shift affecting 18 states taking effect when the 113th Congress takes office in 2013. The political power follows the high population growth, shifting toward the South and West and away from the Midwest and Northeast.

With reapportionment settled, the far more politically divisive process of redistricting is set to begin. In Texas, both major parties were bracing for a showdown over the state’s new residents, beginning a fight that is sure to spark court action. But with Republican supermajorities in the Legislature, the temptation to run the table will be strong.

Rep. Pete Gallego, D-Alpine, said if the federal courts don’t intervene to compel fairness, Republicans will likely produce a map that gives their party the advantage in three or perhaps even all four of the new seats.

“It is very easy to overreach when you’re holding the map and have the pen in your hand,” he said.