In Maryland, Democrats decided that having two conservative members of the U.S. House out of eight was too many, and Republican Roscoe G. Bartlett’s 18-year run in the House ended when they radically changed the composition of his district by adding the Democrat-heavy Washington suburbs.
“You look at the map, and basically they carved it up like a Thanksgiving turkey,” said Tony Campbell, president of Marylanders for Coherent and Fair Representation, which backed the referendum that would have forced the state to redraw its lines in time for the 2014 elections.
Mr. Bartlett is “86 years old; it’s not like he was going to be in office for the next 10 years anyway,” he said, adding that “Maryland is not only dominated by Democrats, but they feel like they can’t be touched.”
The referendum to re-redraw the boundaries got only 36 percent of the vote, which Mr. Campbell attributed to ballot language written by Democrats that simply asked whether voters supported “boundaries for the state’s eight United States congressional districts based on recent census figures, as required by the United States Constitution.”
But the results showed that even many Democrats who were happy to see their party gain seats were disgusted with the way they did so, he said.
On the other end of the spectrum, previous excesses in redistricting have led to the formation of independent, nonpartisan commissions, in California beginning this time and in Arizona a decade ago. The lesser protection to incumbents was immediately visible: Of 63 House seats that changed parties this year, 15 were in California and four were in Arizona.
Data-mining technology has made gerrymandering more effective in the years since computers have become common.
“Over the last couple decades, gerrymandering is definitely getting worse. We’re seeing people really finely tune the lines using the amazing amount of data available. One of the protections against gerrymandering 20 or 30 years ago was simply that the data wasn’t that good,” Mr. Johnson said.
Meanwhile, the means by which the media inform constituents about the people hoping to represent them has lagged behind, with newspapers laying off reporters and struggling to cover one congressman and his challengers now attempting to provide scrutiny of several districts that crisscross through their coverage areas.
“They’re actually divvying up TV and newspaper markets, and the newspapers don’t have the resources to cover them. There’s an added level of advantage to incumbents,” Mr. Johnson said.
Incumbents, who have a built-in financial advantage, also gain when challengers have to pay to advertise in each of those markets. In North Carolina’s 9th District, which is 80 miles long and 1.5 miles wide at points, Republican Robert Pittenger will replace retiring GOP Rep. Sue Myrick, but only after a chaotic campaign in the multimarket district that had 10 candidates in the Republican primary, each with a different geographical base of support.
By Election Day, the race cost more than any other House race in the state, and if Mrs. Myrick were not retiring, no one would have had the resources to take her on.
The Times’ algorithm suggested that new districts across the nation are slightly more compact than those from 2001, in part because of California’s improvements, but that some states, including Louisiana, Kentucky, North Carolina and Illinois, have become worse.
Not all irregularly shaped districts are the result of sheer partisanship. The law also requires the boundaries to afford minority groups the power to be a controlling voice in their districts if reasonably possible. But as with members of one party, “packing” them in great concentrations in one district reduces their influence statewide.
In Florida, Democrat Corrine Brown sailed to re-election after opposing an amendment that would have required the state’s districts to be compact, a stance that put the black legislator at odds with the National Association for the Advancement of Colored People and the state Democratic Party.