Gov. John E. Baldacci will face a challenge from within his own party for the Democratic nomination for governor, with a Gray man submitting enough signatures Wednesday to qualify for the June primary ballot.

Wednesday’s deadline for party-affiliated candidates – including those for governor and the U.S. House and Senate – to file their petitions with the Secretary of State’s Office was the first major test of legitimacy for those campaigns.

Most – but not all – passed.

Christopher Miller, a campaign organizer for presidential candidate Dennis Kucinich in 2004, submitted roughly 2,200 signatures to place his name alongside Baldacci’s on the June 13 primary ballot.

“It’s not about the governor, per se, it’s about Maine’s economic future,” said Miller, who counted the need for alternative energy as among his top concerns.

“We’re looking forward to a strong and hearty debate over the course of the spring and fall,” said Baldacci campaign spokesman Jesse Connolly. “It’s important that we all as Democrats look at all the governor has done in his first term.”

It’s the first time in 24 years a sitting governor has faced a primary opponent. In that 1982 contest, Democratic Gov. Joseph Brennan of Portland handily defeated state Rep. Georgette Berube of Lewiston.

Likewise, pundits said Miller, who is relatively unknown in political circles, isn’t likely to pose a big problem for Baldacci in the June contest.

And Miller’s ability to garner enough support to secure a spot on the ballot doesn’t necessarily signal a deep divide among Democrats, they said.

“If five of these minor candidates – or if somebody like [Maine Sen.] John Martin – made it, that might mean something,” said University of Maine political scientist Mark Brewer. “But I don’t think anyone in their right mind thinks Baldacci will lose a primary.”

Jim Melcher, while sharing Brewer’s prediction of the primary outcome, said a strong showing from Miller could raise doubts about Baldacci’s strength in the general election.

“It would be a negative vote for the incumbent,” Melcher said.

A third Democrat – Robert Bizier of Albion – did not submit the minimum 2,000 signatures needed to earn a spot on the primary ballot.

There were no surprises on the Republican side, with the party’s three major candidates – state Sens. Peter Mills of Cornville and Chandler Woodcock of Farmington, as well as former U.S. Rep. Dave Emery of St. George – all qualifying for the GOP’s June ballot.

J. Martin Vachon of Mariaville, a fourth GOP candidate, did not qualify. He instead will run as a write-in candidate, he said.

Maine Green Independent Party candidate Pat LaMarche of Yarmouth also earned a spot on the June primary ballot. She will not face an opponent in that race.

In the U.S. Senate race, two Democrats will face off in the June primary to see who will represent the party in November against Republican incumbent Olympia Snowe, who is seeking her third term. Jean Hay Bright, an author and political activist from Dixmont, and Eric Mehnert, an attorney from Orono, will vie for the nomination.

Snowe’s prospective GOP primary challenger, S. Charles Tamboia of Ellsworth, failed to gather the required 2,000 signatures. On Wednesday, he said he was disappointed he could not convince enough people to sign his nomination papers.

“They love Olympia, I guess,” he said.

There will be no contested primaries in the state’s two congressional races. Democratic U.S. Reps. Tom Allen of Portland and Mike Michaud of East Millinocket both qualified for the June primary ballots, submitting more than the minimum 1,000 signatures.

Hoping to take Allen’s 1st District seat in November is state Republican Rep. Darlene Curley of Scarborough, who will run unopposed for her party’s nomination in June.

Republican L. Scott D’Amboise of Lisbon, a late entry in the 2nd District race, on Wednesday qualified for the GOP primary ballot, ending any speculation that Michaud might run unopposed in November.

Independent candidates – and there are eight in the governor’s race alone – have until June 1 to submit their petition papers to the Secretary of State’s Office.

There had been nine independents vying for the Blaine House, but on Wednesday, Bobby Mills of Biddeford dropped out of the race and endorsed LaMarche.