BISMARCK, N.D. (AP) - The 8th U.S. Circuit Court of Appeals on Monday affirmed a lower court ruling that a North Dakota election law is constitutional.

North Dakota's Libertarian Party and three of its 2010 legislative candidates sued to invalidate the law, which kept a Libertarian state Senate candidate and two North Dakota House candidates off last year's November general election ballot.

The law says legislative candidates who run in a political party's primary must get a minimum number of votes - equal to at least 1 percent of the population of a candidate's legislative district - to qualify for the general election.

Attorney General Wayne Stenehjem says he's pleased the court recognized that the state has a legitimate interest in reducing ballot congestion and avoiding voter confusion.