RALEIGH, N.C. A Libertarian candidate for governor testified Monday that state law makes it "effectively impossible" to conduct a grassroots campaign in North Carolina.

Mike Munger, a Duke University professor, testified during a civil trial that began one day before the state's primary elections that could determine whether state laws are too stringent and unfairly limit the ability of third parties to get on the ballot.

The Libertarian and Green parties filed a lawsuit that claims state laws that define a political party are onerous and violate party members' rights to free speech and association. The law also affects how party candidates can be included on ballots.

State attorneys defend the law, saying legislators approved rules that maintain the integrity of elections by requiring a political party to demonstrate it has adequate support from voters.

Under the law, a party must collect nearly 70,000 voter signatures to receive official party status. Party leaders said that's one of the highest thresholds in the country. If the party's candidate doesn't get 2 percent of the vote for president or governor, the party must start over. The requirement had been 10 percent until the rules were changed in 2006.

"I'd prefer to be in the primary. What I would like is to have the opportunity to run as a regular candidate," Munger told reporters outside the courtroom. "The lawsuit, you can say, starts now. But I've been running for about three years because we've been having to raise money and pour all of it down a rathole in order to get these signatures. So the fact that the lawsuit occurs right now before the primary is an indication of how disorganized the state is."

The Libertarian Party has surpassed the signature requirement for all but one presidential election since 1976, state attorneys argued in court filings. The Green Party has never met the petition standard.

Special Deputy Attorney General Karen Long, who cross-examined Munger, referred a request for comment to Noelle Talley, a spokeswoman for Attorney General Roy Cooper. A telephone call placed by The Associated Press to the attorney general's office after business hours Monday went unanswered.

Under cross-examination, Munger acknowledged that in this year's election, only four Libertarian candidates have been chosen for the state House, which has 120 seats, and three Libertarians ran for the 50-seat Senate. The party would be able to offer more candidates if it qualifies for the ballot by this year's petition deadline.

Munger also admitted that since 1992, Libertarian candidates had enough signatures to get on the ballot but did not win any state elections. A party spokesman said later Monday the party has won nonpartisan elections.

But the lawsuit, filed in September 2005, said the Libertarian Party has paid more than $100,000 to hire solicitors to collect signatures along with volunteers for a successful petition. The process and money drain favors the state Republican and Democratic parties.

The signature deadline for this year's general election is June 2.