Updated

Democrats have long claimed that Republicans abused their legislative powers to elect a disproportionate number of U.S. House members. Now a Florida court is lending credence to their complaint.

The full impact of the Florida ruling -- plus a similar lawsuit pending in North Carolina -- won't be known for some while. For now, at least, they shine light on the fiercely partisan practice of gerrymandering, in which state officials draw congressional districts to help their party.

Republicans and Democrats have engaged in gerrymandering for decades. Republicans refined the practice in 2011, a year after they won control of numerous state governments preparing to redraw congressional maps based on the 2010 census. It's one reason Republicans hold a solid House majority even though Americans cast 1.4 million more votes for Democratic House candidates than for GOP House candidates in 2012.

Florida is a prime example of Democrats' frustration. President Barack Obama carried the state twice, but Florida's U.S. House delegation has 17 Republicans and 10 Democrats.

A Florida judge ruled Thursday that the GOP-controlled state legislature illegally drew congressional districts to primarily benefit the Republican Party, and ordered them redrawn. The legislature is expected to appeal the ruling, and this fall's elections are unlikely to be affected.

Republicans haven't controlled the White House or U.S. Senate for more than five years. Yet their House majority -- now 234 to 199 -- looks safe this fall. Redistricting episodes in Florida and North Carolina help explain why.

Republicans hold nine of North Carolina's 13 U.S. House seats, and they have solid prospects to make it 10. Their nominee is favored to win a district, which Obama lost by 19 percentage points, being vacated by centrist Democratic Rep. Mike McIntyre.

In recent statewide elections, North Carolina has been about as evenly divided as a state can be. Obama narrowly won it once, and lost it once. Voters replaced a Democratic governor with a Republican in 2012. Each party has one U.S. senator, and this fall's re-election bid by Democratic Sen. Kay Hagan is likely to be extremely close.

The House delegation makeup, by contrast, seems more fitting for a reliably Republican state, like Georgia perhaps.

The arrangement lacks "elemental fairness," said state Senate Democratic leader Dan Blue, moments after attacking Republican school-spending cuts at a Raleigh news conference. The nation's founders, Blue said, could not have envisioned congressional representation falling so out of balance with a state's overall political sentiment.

Several other states have sent more Republicans to Congress than their presidential voting patterns would suggest. Obama carried Ohio twice, but Republicans control its U.S. House delegation 12-4. Pennsylvania hasn't backed a GOP presidential nominee since 1988, but it has 13 House Republicans and five Democrats.

The House makeup is similar in other states that Obama won twice, including Virginia (8-3 Republican), Michigan (9-5 Republican) and Wisconsin (5-3 Republican).

The only state trending the other way is Arizona. Obama lost it twice, yet it has five House Democrats and four Republicans.

A chief reason for the imbalance is the often politicized state-by-state practice of redrawing the House's 435 districts after each once-a-decade Census. Districts are apportioned by population, with each state getting at least one House member.

Americans' mobility patterns also helped, as millions of liberals continue to move to urban areas. This so-called "self-gerrymandering" makes it easier for Republican mapmakers to pack as many Democratic voters as possible into a handful of districts. That helps Republicans win a larger number of districts by smaller but still-safe margins.

In North Carolina, Republican officials drew three House districts that twisted and snaked to include as many black neighborhoods, and other likely Democratic areas, as possible. In the 2012 elections, these three districts recorded overwhelming Democratic majorities. Obama lost the other 10 districts by margins ranging from 13 to 23 percentage points.

Republicans won their 9-4 U.S. House edge even as North Carolinians cast more votes for Democratic House candidates overall.

Democrats are asking the state Supreme Court to rule the redistricting unconstitutional. Black voters were packed so densely into three districts, they contend, that their overall political clout was unduly diminished.

"We've got a red government imposed on a purple state," said Ferrel Guillory, a University of North Carolina professor who advised the plaintiffs.

Republicans defend the map, noting that they followed state laws enacted when Democrats controlled the government. "We would expect our maps to be vindicated completely," GOP state Sen. Bob Rucho said at the time.

David Rouzer, who had been an aide to Republican Sen. Jesse Helms, came within 654 votes of ousting McIntyre in 2012 in the 7th District, which includes several southeastern counties. Now that McIntyre is retiring, Rouzer is favored to win.

Relaxing in a Raleigh coffee shop before a recent fundraiser, Rouzer said McIntyre had found it harder and harder to persuade anti-Obama voters to support him. "A lot of people feel like the country is in big trouble," Rouzer said, citing the federal deficit, unemployment and other concerns.

Democratic Rep. David Price, D-N.C., who has spent 25 years in Congress, sees political chicanery in North Carolina's U.S. House map.

"It's the most extreme gerrymandering, on a purely partisan basis, I think we've ever seen," Price said.