PORTLAND – A new poll Thursday shows Republican Susan Collins with a 14-point lead over Democratic challenger Tom Allen among registered voters in this fall’s U.S. Senate race in Maine.

The poll by market research firm Critical Insights of Portland found 51 percent support for Collins, the incumbent, and 37 percent for Allen, a sixth-term congressman. About 1 in 10 were undecided.

Independents, who make up Maine’s largest voting bloc, went for Collins 61 percent to 27 percent. Collins also was backed by more than one in four Democrats, while 9 percent of Republicans broke for Allen. Among “highly likely” voters, Collins led by 10 points.

The poll of 602 registered voters was conducted between June 1 and June 27 and claims a margin of error of plus or minus 4 percentage points.

The Allen camp said the numbers at this stage in the campaign largely reflect name recognition, where Collins has a natural advantage.

“We do know that the numbers are moving,” campaign spokeswoman Carol Andrews said. “Things are going to move drastically and quickly once the TV wars begin.”

Both sides have large war chests in what is already Maine’s most expensive campaign ever. But aside from a Collins ad that began appearing in recent days, the anticipated barrage of television spots has barely begun. Andrews said she expects that to happen in the coming weeks.

Collins’ campaign manager, Steve Abbott, took the latest poll results in stride.

“Every poll that’s come out in this race has shown Senator Collins with a substantial lead and we try not to get distracted or pay attention to any of them,” he said. “We know we have a lot of work to do between now and November and we’ll keeping working hard regardless of what the polls show.”

In other findings, the poll showed that 71 percent have an unfavorable view of President Bush, the lowest since the question first was asked six years ago. Fifteen percent thought favorably of the president and 14 percent were undecided.

Bush’s lack of support extended even to Republicans, where the breakdown was 42 percent unfavorable to 38 percent favorable.

Gov. John Baldacci’s approval rating sank to the lowest level since he took office, with 48 percent saying they disapprove of the way he is handling his job. Thirty-nine percent expressed approval and 13 percent said they don’t know.

The economy was far and away the top issue facing Maine, according to 36 percent of respondents, the largest proportion for any issue in the history of the survey. Nine in 10 said they thought the economy has gotten worse in the past year and 55 percent think it will decline over the coming year.