enlarge Gordon Chibroski/Staff Photographer

Chellie Pingree chats with Barbara Fiore of Portland at an event sponsored by the League of Young Voters.

enlarge Tim Greenway/Staff Photographer

Maine state Sen. Ethan Strimling greets Merle Steva of Saco during a pancake breakfast at the Unitarian Universalist Church.

FOLLOWING THE RULES

FEDERAL CAMPAIGN FINANCE RULES cap contributions from individual donors to candidates at $2,300 for the primary and an additional $2,300 for the general election.

CANDIDATES ALSO can receive contributions from political action committees, which are often set up by business or labor groups; those contributions are capped at $5,000 for the primary and an additional $5,000 for the general election.

OTHER OUTSIDE GROUPS, called 527s after the section of IRS code that establishes them, can publicly advocate on behalf of issues, but not for specific candidates. Contributions to those groups are not capped.

FUNDRAISING TOTALS

Eight candidates are vying to succeed Democratic Rep. Tom Allen, who is leaving the 1st District seat to challenge Republican Sen. Susan Collins. Here is how much money each raised as of March 31:

DEMOCRATS

CHELLIE PINGREE: $1,114,163

ETHAN STRIMLING: $500,700

ADAM COTE: $460,310

MARK LAWRENCE: $415,619

MICHAEL BRENNAN: $210,489

STEVE MEISTER: $60,442

REPUBLICANS

DEAN SCONTRAS: $232,425

CHARLIE SUMMERS: $182,698

The Democratic primary race in Maine's 1st Congressional District has taken a negative turn, with the two candidates who have raised the most money at odds over contributions from a wealthy hedge-fund manager and leveling charges of political mudslinging at each other.

At the center of the dispute between Democrats Chellie Pingree and Ethan Strimling is a financier named S. Donald Sussman, who lives in the U.S. Virgin Islands and also has a home on Deer Isle.

Sussman has given Pingree's campaign $4,600, the maximum allowable contribution. His colleagues at Paloma Partners, a hedge fund incorporated in Delaware, have given an additional $46,400 to her campaign, according to campaign finance records.

The contributions are legal, but Strimling has seized on them to attack Pingree, who as of March 31 had raised $1.1 million – more than twice as much as any of the other five Democrats vying to replace Rep. Tom Allen. Allen is challenging incumbent Republican Sen. Susan Collins this year.

Strimling is second among the Democrats in total cash raised, with $500,700 collected through the end of March. The winner of the party's June 10 primary will face the Republican nominee in the Nov. 4 general election.

Strimling, 40, of Portland has made an issue out of the hedge-fund contributions at a time when he and Pingree, 53, of North Haven, have offered similar views on the Iraq war, health care and other issues. The focus of Strimling's criticism has been to try to draw a contrast between Pingree's deep-pocketed contributors and her background championing campaign finance reform as the former president of the advocacy group Common Cause.

Hedge funds, which are private investment funds typically open to a limited number of wealthy investors, have become a political hot button in part because they are loosely regulated. In addition, hedge-fund managers benefit from a tax loophole that allows the money they make to be treated as capital gains rather than income, which means their money is taxed at a lower rate.

"When someone is dumping that kind of money into your campaign, you have to ask, Why are they interested? Why are they doing that?" Strimling said. "I'm just disappointed and surprised."

Pingree says that she favors closing the tax loophole and supports tighter regulation of the hedge-fund industry. She said in an interview that if elected, she won't be influenced by her contributors' money.

"I don't think that anyone who donates money to me has any illusions about how I will vote," Pingree said. "I'm about as progressive as you can get, and I'm never going to change where I stand or how I vote."

Sussman has donated money to Pingree before. In 2002, he gave $300,000 to a joint fundraising committee, established with the Democratic Senatorial Campaign Committee, that was set up to help Pingree in her campaign against Collins, which was unsuccessful. Under the law as it existed in 2002, the group was allowed to accept unlimited contributions, a fundraising tactic that Pingree said at the time that she wanted to ban.

Also in 2002, Sussman donated $303,700 to the Fund for Maine's Future, an environmental political action committee. Between 2004 and 2006, he gave $165,000 to the Maine Democratic State Committee.

Though Pingree agreed to talk about her views on regulation of the hedge-fund industry, her campaign did not make her available in response to a later interview request to discuss Sussman.

Pingree's campaign spokesman, Willy Ritch, said that Pingree and Sussman know each other, but did not know each other in 2002. He declined to answer questions about their relationship, including when and where Pingree and Sussman met. "We consider him a loyal supporter and friend," Pingree's campaign said in a statement.

Sussman declined to answer questions for this article. He released a statement through a Maine business associate, Kevin Mattson,...