The increasingly widespread - and perfectly legal - practice of gerrymandering is having a serious and lasting effect on American democracy, as the BBC's James Silver reports from Texas.
Some are standing down rather than running in a new district
The sight of cowboys being abruptly unseated by the bucking broncos at the rodeo in Mesquite, Texas, must surely strike a chord with many of the state's Democratic Congressmen.
Thanks to gerrymandering - the redrawing of district boundaries for partisan advantage - several of them are set to lose their seats in November.
Using sophisticated computer programmes, political boundaries are being redrawn across the US to all but guarantee results.
Gerrymandering is quietly, but dramatically, changing the face of American democracy.
Today, only a handful of Congressional seats are truly competitive.
Simply by redrawing the lines of his district with the click of a mouse, the Republicans - who hold power in the state of Texas - have forced Democratic Congressman Jim Turner into a district he knows he can't possibly win.
That's why, come November, he will be standing down.
"The redistricting lines which were drawn by the Republicans in Texas were clearly aimed at trying to eliminate as many Democrats as possible from the state's delegation to Congress," he told BBC Radio 4.
"I happened to be the member that was targeted most effectively, because my district was cut into six different pieces and the part that I live in was put into a district that's been represented by a Republican congressman for almost 20 years.
"This is a dangerous trend. We know democracy is not promoted if we end up with partisan politicians selecting their constituents rather than the other way around."
The term gerrymandering can be traced back to 1812, when Massachusetts Governor Elbridge Gerry fashioned a district for political purposes in the shape of a salamander.
It has been part of the political landscape in America ever since.
Every decade, with the publication of a new census, all US states are obliged to redraw the boundaries of their congressional districts.
With a handful of exceptions, the process is carried out by the party in control of the state legislature.
In Texas, there was deadlock between the parties in 2001 - the regular year for redistricting - so the job was handed to the courts.
They drew boundaries which by and large preserved the congressional majority of the Democrats.
However, when the Republicans gained complete control of the state of Texas in 2002 - for the first time in 130 years - they took the unprecedented decision to return to the redistricting table mid-decade.
Frost says gerrymandering can affect how laws are made
Jim Turner may be standing down, but five of the seven Democrats affected by the new map have decided to fight on.
They include Congressman Martin Frost, who has represented district 24 of Dallas-Fort Worth for 26 years.
Congressman Frost claimed that the Republicans "were trying to turn Texas into a one-party state".
But, he continued, the shadow of gerrymandering falls on far more than just the state of Texas - it falls across national government too.
"Gerrymandering can be used by one party or the other to preserve their majority in the House of Representatives long past the time they have a majority in the country.
"It can also alter the course of legislation which can cause the Congress to move in a direction which is contrary to majority sentiment in the country."
Forced out of his own district by the new plan, Mr Frost is now running in a Republican-leaning district containing far fewer natural supporters.
Little support, little sympathy
He thinks he can win, but many observers do not share his confidence. There is little sympathy for him either.
Prior to last year's map redistricting, the most significant gerrymander in Texas was carried out by the Democrats in 1991.
They carved up the state to favour their side, and the figure at the helm that year was a certain... Martin Frost.
That's why the 2003 redistricting bill in Texas was widely perceived to be "payback" for the Republicans.
The man who steered it through the State House was Republican State Representative Phil King, who lives in the town of Weatherford, one hour west of Dallas.
With its streets lined with white picket fences, its clipped lawns and billowing flags, Weatherford is classic conservative, small-town Texas.
Mr King is a refreshingly straight talker, who places his Christian faith at the heart of his politics.
Outside his law practice is a sign listing the Ten Commandments.
Mr King is blunt about what he set out to do - namely, "to undo" Martin Frost's 1991 Democrat gerrymander and secure a majority in the US House of Representatives for the Republicans.
"The redistricting bill was something myself and some other members had begun to work on several years earlier because we knew that it was right for Texas," he said.
King is frank about his plan's aim to ensure Republican control
"We knew that if we could add five to seven seats to the Republican numbers in Congress it would be virtually impossible for the Republicans to lose the majority in President Bush's second term."
Texans, Mr King argued, back the Republican party. In the 2000 election, George W Bush got nearly 60% of the popular vote to Al Gore's 38%.
"It was very important for me to make sure that our president from Texas, George Bush, had a Republican House to work with in his second term.
"We drew a map that probably increased Republican seats from 15 to maybe 22 out of 32 seats in a really good year. It's not what you'd call a political coup.
But Rob Ritchie, director of the Center For Voting and Democracy, says that as a consequence of gerrymandering, kicking out incumbent members of Congress verges on the impossible and competition in Congressional races has all but vanished.
"One of the stark realities of our politics now is that fewer than one in ten House races is competitive today," he said. "That means that almost from the get-go, more than 90% of races can be safely put in one party's camp.
"In 2002, out of 435 seats, only four incumbents lost to challengers, the fewest ever in our whole history."