If Congress were a business, it would be investigated by the Justice Department for antitrust violations.

U.S. House members long ago decided that elections were costly and bothersome, so it fixed congressional boundaries to preclude competition. Districts were made either heavily Democratic or heavily Republican. Voters could choose the Democrat of their choice or the Republican of their choice, depending on the district in which they lived.

During the past decade, only three of North Carolina's 13 congressional districts changed parties. That is 65 House elections, and three party changes. In other words, there was about a 5 percent chance a congressman would lose.

The Democrats were able to pick up two swing seats during the Democratic upswing in 2006 and 2008, and the Republicans picked up a swing seat in 2010.

That was it for the decade.

But 2012 will almost certainly bring big changes, due mainly to the redistricting plan passed by the Republican legislature - assuming it is upheld by the courts.

There will be two new North Carolina congressmen elected this year to replace two Democrats who chose to retire after being placed in districts in which they could not win - Brad Miller of Raleigh and Heath Shuler of Bryson City. A third House member, Republican Sue Myrick chose not to seek re-election.

Two other members of Congress could also lose their jobs. Democratic incumbents Larry Kissell of Biscoe and Mike McIntyre of Lumberton are fighting for their political lives, after having been placed in more GOP leaning districts.

So we could easily see five new members of Congress this year - the biggest turnover since the Republican landslide of 1994.

This has provided a rare opportunity, mainly for Republicans, and that was reflected in the candidate filings, which ended last week.

Seventy-two candidates filed for the 13 congressional seats - 48 Republicans and 24 Democrats.

There are hot Republican primary races all across the state, including one in the Triangle for Miller's 13th District seat that features two high profile candidates: Wake County Commissioners Chairman Paul Coble, a former Raleigh mayor; and former U.S. Attorney George Holding.

The North Carolina House delegation now has a 7-6 Democratic majority. It is the only state in the South with a Democratic majority, but not for long.

There is a good chance the delegation could be 10-3 Republican by next January.

But the competitive races in 2012 are likely to be an outlier. Once the new Republican incumbents settle in to friendly districts, they will use the advantages of incumbency just as the Democrats did.

The newly aligned congressional districts are not designed to foster competition, but to elect Republicans.

So enjoy this year's races, because for the rest of the decade we are likely to return to noncompetitive elections.

rchristensen @newsobserver.com or 919-829-4532