So Hill tried something. He went negative.
He attacked his Republican opponents, who both complained he was being nasty and unfair when he called them tax-and-spend liberals in bad disguises.
But the strategy worked. Hill rallied in the final weeks of the campaign and won the primary with 44 percent of the vote, eight points more than his closest opponent.
Now Hill, a wealthy Helena businessman, faces Democrat Bill Yellowtail, a Crow Indian rancher from Wyola who gave up a $120,000-a-year job as the Environmental Protection Agency's top man in the Rocky Mountain region in order to run for Congress.
Democratic polls over the summer said Yellowtail had a slight lead. He is the more obvious successor to the popular Pat Williams, a Democrat who represented the district for the past 18 years. Williams was hugely popular with Native Americans; his efforts on their behalf ranged from helping Indian colleges get land-grant status to changing the name of the Custer Battlefield to the Little Big Horn Battlefield. He was well-liked by environmentalists, and his pro-union stance also won him the mining vote.
Williams has endorsed Yellowtail. But if Hill continues to trail in the race, the campaign could get nasty, observers say.
Hill, 49, has shown an aptitude for negative campaigning and Yellowtail, 48, has a past that would make such tactics easy; it includes burglary, spouse abuse and several years as a deadbeat dad. As a student at Dartmouth College almost 30 years ago, he burglarized a camera store, was convicted and subsequently thrown out of school. Then, in the 1970s, he once struck his wife in the face so hard he had to take her to the hospital.
By 1986 the couple had been long since divorced and Yellowtail had become a state senator. But he had fallen $7,200 behind in his $100 monthly child support payments and his ex-wife had to garnish his Senate wages to get it from him.
Yellowtail points out that all these things happened many years ago. The governor of New Hampshire pardoned him, and Dartmouth readmitted him and let him graduate. His ex-wife and his daughter both actively support his campaign.
The people most directly harmed by his actions have forgiven him; Yellowtail says voters should do the same.
So far, Democrats have done so in droves. Despite a late entry into the race and headlines blaring his past sins, he took 56 percent of the primary vote, more than all three of his opponents combined.
Few people believe Republicans will be so magnanimous.
"I don't expect them to run ads saying they forgive him," said Larry Jent, one of the people Yellowtail beat in the primary.
It would be hard to find two candidates with less similarity in issues, style and personality.
Hill is short and pugnacious. A champion 115-pound high school wrestler in his native Minnesota, he remains a high-energy scrapper in his party's conservative wing. He strongly opposes abortion, is a fiscal conservative, touts family values despite his own long and acrimonious divorce, and says he wants to unshackle America's entrepreneurs from the twin burdens of taxation and regulation.
Environmentalists, he said, believe "mankind is the cause" of problems. But they're wrong. "We're the ones that put value on nature."
The emphasis of politics should be on the economy, he maintains.
"When you lower taxes, the economy does better," he said. "Government regulation is like friction on the economy. It costs money."
Yellowtail is tall, slow-moving and quick to laugh - he once introduced a bill to designate the magpie as Montana's state bird.
He favors some gun control and wants wilderness and water protected. He wants family farms supported, talks a lot about sustainable communities and dismisses Hill's economic plans as "that tired old trickle-down theory." He strongly supports education and earned high marks from environmentalists and from liberal women's groups while in the state Senate.
Women voters could play a critical role in the election. Montana has only about 560,000 registered voters, a little more than half of them women. Traditionally, both parties can count on about 40 percent of the vote. That leaves 110,000 independent or "swing" voters, half of whom are women.
The child support and spouse abuse incidents could be major deciding factors for some of those women.
Yellowtail said he's confident he can win them over.
"I don't ask them to excuse these egregious mistakes," Yellowtail said. "I have talked to lots and lots of women, and in view of my baggage, have walked away with lots of support. They (women voters) have shown me they're looking forward, not backward."
* Scott McMillion
Scott McMillion reports from Livingston, Montana.