WASHINGTON -- Marijuana activists may gain an unexpectedly high-profile champion for their cause next year, thanks to Bob Kerrey's sudden decision to jump into the Nebraska contest for retiring Sen. Ben Nelson's seat. Pot reformers have their fingers crossed.

Kerrey, a Democratic senator for Nebraska in the 1990s, has a scant public record of support for marijuana legalization so far. But several longtime advocates for rewriting pot laws point out that he has a history of advising his old friend Peter Lewis, the billionaire founder of Progressive Insurance and the leading financial backer of marijuana policy reform, on Lewis' efforts. Kerrey has known Lewis for decades. His role in advising Lewis on pot policy was first reported two years ago.

In a Huffington Post blog post in 2010, Kerrey called on the Department of Veterans Affairs to let doctors inform veterans about medical marijuana.

And one longtime activist told HuffPost that since Kerrey left his job as president of New York's New School a year ago, the word in the activist community has been that Kerrey has been among a close group of people offering advice to Lewis, who is supporting marijuana ballot measures in Washington and Colorado.

Graham Boyd, a former lawyer with the American Civil Liberties Union who works closely with Lewis, confirmed that Kerrey and Lewis talk, but would not detail what they talk about.

Kerrey's campaign boss, Paul Johnson, said it was most definitely not about marijuana.

"Bob Kerrey and Peter Lewis are good friends," Johnson said by email. "But the notion that Sen. Kerrey was or is a part of a small group advising Mr. Lewis on strategy in New Hampshire or any other state is false."

Rob Kampia, the executive director of the Marijuana Policy Project (MPP) -- which Lewis used to back with several million dollars per year -- said that Kerrey has advised Lewis on marijuana strategy in the past. Kampia described Kerrey's involvement in a project that aimed to get presidential candidates in the 2004 race on the record on medical marijuana.

"In 2003, Peter asked Bob for his feedback on MPP's tentative plan to spend $250,000 to influence the presidential candidates' public statements about medical marijuana in New Hampshire," Kampia emailed. "Bob was kind enough to provide a one-page analysis, which essentially said that the project was worthwhile, but that it could be accomplished by spending less money; as a result, we ended up spending about $60,000 on that project, which was quite successful at getting all the candidates on the record."

Kampia also noted that the activists had considered trying to get Kerrey more formally involved in the effort.

"At one point, Peter and I talked about the possibility of retaining Bob to lobby for MPP on Capitol Hill, but I don't recall if Peter actually spoke with Bob about it," Kampia wrote. "In any case, that never went anywhere. Instead, we retained a different Bob to lobby for us a few years later -- Bob Barr."

Kampia added, "To be clear, I don't recall if Bob Kerrey ever explicitly said he supported legalizing medical marijuana in his communications with Peter Lewis and me. I do recall that he wrote something positive to a constituent when he was a U.S. senator in the 1990s, but I doubt the MPP staff would be able to find that letter today."

As for that HuffPost commentary, Kerrey, a Medal of Honor awardee who lost part of a leg in Vietnam and had a role in a notorious war massacre, argued that cannabis has been shown to help treat chronic pain from wounds and post-traumatic stress disorder without the troubling side effects of some other drugs.

Exactly how Kerrey's stance on pot will play in Nebraska is unclear, but four ballot initiatives on marijuana are being advanced by activists there, including two that would decriminalize the plant by amending the state constitution and two that would allow medicinal use of marijuana.

One key local activist thought Kerrey could help the cause. "I know that he is a very strong advocate for marijuana reform. At least, that's what I've been hearing," said John Smith, director of Nebraska's branch of the advocacy group NORML, which is backing two of the measures.

None of the measures are on the ballot yet, with the amendments requiring more than 120,000 signatures to qualify and the proposed laws needing about 85,000. But the effort could well make legalization a campaign issue, and Smith suggested that could be to Kerrey's advantage.

"I think it will get him the votes, especially on the medical end," argued Smith.

It could also pose a risk for Kerrey, whom Republicans are already trying to cast as too liberal for Nebraska. Rob Jesmer, director of the National Republican Senatorial Campaign, argued Monday that Kerrey "isn't just far more liberal than many of his friends in Washington –- he also has far more serious electability problems than Ben Nelson ever did."

Still, Kampia sees an opening for Kerrey, pointing to a February 2002 survey paid for by MPP that found 64 percent support for medical marijuana laws in the Cornhusker State.

"If I were providing political advice to Bob Kerrey, I'd recommend that he state his 'support for removing criminal penalties for seriously ill patients who need to use marijuana for medicinal purposes,'" Kampia said, referencing the survey language used at the time.

Ryan Grim was a low-level staffer at MPP during 2004, but had no direct knowledge of Kerrey's involvement at the time. He's the author of "This Is Your Country on Drugs: The Secret History of Getting High in America."

Related on HuffPost: