AUGUSTA – State election officials opened a review Monday of a challenge to the nominating petitions of an independent candidate for the U.S. Senate brought by the chairman of the Maine Democratic Party.

With an administrative decision likely within about a week, the proceeding is being closely monitored by Republicans as well as the Democrats.

Retired psychologist Herbert Hoffman of Ogunquit, a former Democrat, says his would-be candidacy would advocate an immediate halt to the war in Iraq and the establishment of a single-payer universal health care system.

He also criticizes Republican nominee Susan Collins, who is seeking a third Senate term, and Democrat Tom Allen, the sixth-term representative from Maine’s 1st Congressional District, for failing to hold the Bush administration accountable.

Hoffman’s petitions for candidacy contain 4,112 valid voters’ signatures, as originally determined by election officials, 112 more than the 4,000 required by state law.

John Knutson of Brooklin, chairman of the state Democratic organization, did not testify at a secretary of state’s hearing Monday as his challenge, supported by party Executive Director Arden Manning and a legal team brought in by the party, was presented. But his side claims that some petition signatures are invalid and that there are questions about whether Hoffman’s petitions were handled properly.

Questioned by Hoffman attorney John Branson, Manning said he had spoken with the Allen campaign about the status of Hoffman’s petition signatures but that the challenge was “a personal decision” by Knutson.

“This was strictly an internal discussion we had,” Knutson added in a brief interview during a break in the hearing.

Branson, meanwhile, told reporters that Democrats were creating “a sham” to mask the party’s central role.

Allen campaign spokeswoman Carol Andrews played down the role of the Democratic candidate’s organization from the inception of the challenge.

“We didn’t have to be asked. They went ahead on their own,” she said.

Asked about Hoffman’s potential effect on an otherwise two-way race, Andrews said the Allen camp would prefer that Hoffman did not run and remained hopeful that he would come over to the Democratic congressman’s side.

“He shares many of our views, most of our views,” she said.

Hoffman said neither major party candidate had been involved in his decision to run.

Collins’ aide Steve Abbott was happy to agree.

“We are not behind his candidacy,” Abbott said.

The Secretary of State’s Office has determined that another independent, Laurie Dobson of Kennebunkport, failed to submit enough signatures to get on the ballot by the late-May deadline. Officials said Dobson was 160 signatures short of the minimum.

On June 3, Dobson requested extra time to submit additional signatures, but election officials denied her request, saying they did not have the legal authority to do so.