Former Massachusetts Senator Scott Brown has attempted to revive his political career by running for Senate in New Hampshire. But in the final days before his September 9 primary, he's squaring off against another opponent — Harvard professor Lawrence Lessig, who advocates against money in politics. Lessig's Mayday PAC endorsed Brown's GOP primary challenger Jim Rubens, and is now sending out a mailer calling Brown a "Washington lobbyist."

Brown worked for a "law and lobby firm"

The mailer led to an angry response from the Brown campaign. "This is a flat-out lie. Scott Brown is not nor has he ever been a lobbyist. Ever," campaign manager Colin Reed wrote, calling on Lessig to "immediately cease and desist with the mailer in question."

In response, Lessig posted the letter on his blog, and linked to an article from The Hill about Brown joining the Boston office of "Nixon Peabody, a law and lobby firm." The firm itself said Brown would work on "business and governmental affairs," including those related to "the financial services industry." Lessig writes:

Yes, according to the Senate, Scott Brown isn't a "lobbyist." But I submit to anyone else in the world, a former Senator joining a "law and lobbying firm" to help with Wall St's "business and governmental affairs" is to make him a lobbyist. Because to anyone else in the world, when you sell your influence to affect "business and governmental affairs," you are a lobbyist.

Brown has been a top target of campaign finance reformers this year. In the months after Brown joined the Senate in 2010, many reformers lobbied him aggressively to support the DISCLOSE Act, which would have increased disclosure for groups spending dark money on federal elections. The bill failed to clear a filibuster by just one vote — a filibuster Brown supported. The primary election has only been polled once in recent months, but if Brown wins, he'll attempt to unseat Senator Jeanne Shaheen this fall.

Update: Added link to a new poll on the race.