PORTLAND (AP) – Mainers favor Gov. John Baldacci over three top GOP challengers but they continue to worry about the economy, according to a poll released Tuesday.

The Strategic Marketing Services survey gave Baldacci an advantage of more than 10 percentage points in different scenarios against Republicans David Emery of St. George, Peter Mills of Cornville and Chandler Woodcock of Farmington.

But the poll also showed that more than a third of voters are undecided and that there’s widespread dissatisfaction with the state’s economy.

The economy continues to be the top issue on the minds of Mainers – scoring higher than health care and taxes, the poll showed.

It also indicated 54 percent of respondents feel that Maine has lost more jobs than it has created over the past three years despite the Baldacci administration’s contention that there has been a net gain of 4,600 jobs since 2003.

Christian Potholm, a political science professor at Bowdoin College, said all of the elements are in place for a competitive gubernatorial campaign with third party and independent candidates playing a big role in the ultimate outcome.

“I think it’s going to be quite an exciting campaign for a change,” he said. “Everything is sort of up for grabs, and that’s sort of unusual.”

The statewide telephone poll of 400 likely voters was conducted March 3-8 by Strategic Marketing Services, which conducts the quarterly survey. The margin of error was plus or minus 5 percentage points.

The poll provided an early snapshot of the gubernatorial race by pitting Baldacci against three GOP candidates who submitted nominating petitions to state election officials three months ahead of the June primary.

It showed Baldacci with a 13-point lead among those who planned to vote for him or were leaning toward voting for him over both Emery, former 1st District congressman, and Mills, a state senator. Baldacci’s lead was wider – 18 points – over Woodcock, also a state senator. The poll didn’t include little-known J. Martin Vachon of Hancock County.

State Rep. Barbara Merrill of Appleton, who quit the Democratic Party before going independent, had 4 to 6 percent in the various scenarios, followed by former Lewiston Mayor John Jenkins and the Green Independent Party’s Pat LaMarche, the poll said.

Despite a comfortable lead, however, Baldacci never gained more than 36 percent of the support of respondents who said they supported him or would likely support him.

“I think Baldacci has a good lead but he certainly can’t sit back on his laurels. He has got to take his fair share of those undecided voters,” said Patrick Murphy, president of Strategic Marketing Services in Portland.

On another topic, the poll showed that more than half of respondents, 56 percent, either “strongly” or “somewhat” support a referendum question seeking to establish a Taxpayer Bill of Rights. The so-called TABOR proposal would limit government spending to the rate of inflation plus population growth.

Twenty-one percent of the respondents said they oppose the measure, and 23 percent didn’t know.

Murphy noted that there also was early support for a tax cap proposal on the November 2004 ballot, but the support eroded closer to the election. Mainers ultimately rejected the tax cap referendum by a solid margin.

“Certainly the TABOR folks are starting out with a very strong hand. On paper, it looks like an attractive proposition to people,” Murphy said.