By David Lightman

Black residents of Riviera Beach, a small southeast Florida town, like their congressman.

Rep. Alcee Hastings looks like them. He understands them. "If the person has the same race as you, I think they care about you more. They understand where you come from," said Michael Foreman, a personal trainer.

Hastings, a black Democrat, represents a surgically drawn district where a majority of the population is black, one of dozens of majority-minority districts around the country.

For three decades, lawmakers have increasingly crafted similar districts so that historically underrepresented populations will have adequate representation. And the roster of minorities in Congress has jumped, with the number of African-Americans more than doubling. The vast majority are Democrats, like Hastings.

This jagged line-drawing has had another effect: It's created what the highest-ranking black member of Congress called "political ghettos," shoehorning racial minorities into those districts and making it easier for Republicans to win in surrounding areas. That's helped the Republicans win and maintain majorities in the House of Representatives. And it helps explain why the two major parties can get roughly the same number of popular votes nationwide yet give the GOP more seats in the House. In 2012, Democrats actually got slightly more of the national popular vote, yet the Republicans today have a 233-199 majority in the House, an edge that's expected to grow.

If Democrats were elected based on their share of the popular vote, said David Wasserman, House editor at the nonpartisan Cook Political Report, the party would have gained 19 more seats in 2012 and probably had a House majority today.

The clustering of Democrats "hurts them a great deal," he said.

Majority-minority districts have mushroomed since the 1980s, when the Voting Rights Act helped give racial minorities a better chance to elect candidates of their choice. The nation had 35 majority-minority districts in 1982. Today it has 118, according to Wasserman. About 1 in 5, 88, have non-white majorities among the voting age population, according to FairVote, an organization that seeks to make elections fairer.

While the original goal may have been to ensure minority representation in the government, the every-decade drawing of new congressional district boundaries took on a partisan air.

Republicans realized in the early 1990s that packing districts with reliably Democratic minorities improved Republican chances in next-door districts, and Democrats who wanted the majority-minority districts would go along. The strategy helped Republicans win control of the House in 1994 for the first time in 40 years, and the party has controlled the chamber for all but four of the last 20 years.

Courts have noticed, as lawsuits challenged the notion that district maps unconstitutionally categorized voters by race. Earlier this month, a federal court in Virginia ordered that state's legislature to redraw the lines for Virginia's 3rd Congressional District after the November election.

The district is a majority-minority hodgepodge that stretches roughly 70 miles from Richmond to Newport News, carefully drawn to include as many black voters as possible.

Rep. Robert Scott, a Democrat, was first elected to the seat in 1992, the first black since Reconstruction to win a congressional seat in Virginia. He's the only black in the 11-member delegation in a state where 20 percent of the population is black.

The Republican-led General Assembly passed a plan that added thousands more black residents to the 3rd District in 2012. Scott didn't need them. Over 20 years, he's won his seat with a range of 69 percent to 97 percent of the vote.

But by adding more minority Democrats to his district, it took them out of neighboring districts _ making them safer for Republicans. "Tellingly, the populations moved out of the 3rd Congressional District were predominantly white, while the populations moved into the district were predominantly African-American," the court majority found.

Nationally, Republican leaders said they are not engaged in race-packing. "Not at all," said Rep. Greg Walden of Oregon, chairman of the Republicans' House campaign committee.

Anyway, he said of the line drawing, "I don't know that it makes that much difference."

It can make a difference. In southeast Florida, Hastings, whose district is about 54 percent black, won his last election with 88 percent of the vote, and he's expected to coast again. He shares a boundary with Rep. Patrick Murphy, a white Democrat who eked out a 2012 victory with 50.4 percent. Murphy's district's is 13 percent black.

Move some of Riviera Beach's black population into Murphy's district and he would probably have an easier time. Moving boundaries like that could be repeated throughout America and still leave minorities as majorities. "These lines do make it harder for us to play in other areas," said Rep. Marcia Fudge, D-Ohio, the Congressional Black Caucus chair.

"You create political ghettos where you stack the minority voters in one district and thereby bleach out the others," said Rep. James Clyburn of South Carolina, Congress' highest-ranking black Democrat. "It's unconstitutional and also unconscionable."