BANGOR – She has more than $2 million in the bank and some of the highest approval numbers of anyone on Capitol Hill.

Toppling U.S. Sen. Olympia Snowe in her effort to keep her seat isn’t expected to be an easy task, experts say, as the Republican launched her 2006 campaign during a statewide tour Thursday.

“Maine people deserve a voice in Washington as resolute and independent and reasonable-minded as Maine people themselves,” Snowe told a group of about 50 supporters at Husson College. “I believe I have been that leader for you in the United States Senate.”

Snowe, 59, is running for her third term in the Senate. Thursday’s kickoff of her re-election campaign also included stops in Portland, Auburn and Presque Isle.

During her tenure in Washington, Snowe has earned a reputation as a moderate willing to buck her party on occasion. Some recent examples include her efforts to limit the Bush administration’s tax cuts and scuttle its plan to privatize part of the Social Security system.

In November Snowe will face one of two Democrats – Jean Hay Bright of Dixmont or Eric Mehnert of Orono – vying for their party’s nomination. Snowe does not have a primary opponent.

Most political observers consider either Democrat a long shot against Snowe, whose job approval ratings top 70 percent among her Maine constituents and whose campaign coffers already hold $2.1 million.

“She is an extremely formidable candidate,” said L. Sandy Maisel, a Democrat and political scientist at Colby College.

“I can’t see Democrats really going after her and investing a great deal of resources in this race if it can’t happen,” said Maisel, predicting the party would instead target more vulnerable Republicans such as U.S. Sens. Lincoln Chafee of Rhode Island and Rick Santorum of Pennsylvania.

In terms of money, the Democratic hopefuls in Maine are at a severe disadvantage.

With a new round of financial reports due Saturday, Hay Bright had raised just $25,000 and had spent all but a few hundred dollars, according to her campaign treasurer. Mehnert could not be reached for comment, but as of Dec. 31, 2005, the civil rights attorney had raised only about $4,500.

But Democrats say they are intent on reclaiming control of the Senate, and a spokesman for the Democratic Senatorial Campaign Committee said Snowe is closer to Bush’s increasingly unpopular agenda than her reputation suggests.

“Olympia Snowe votes with George Bush eight out of ten times. A vote for her is a vote for the rubberstamping Republican Senate majority that blindly advances the president’s radical agenda,” said DSCC spokesman Karl Frisch.

Hay Bright, an author and organic farmer, also attacked Snowe’s moderate standing.

“She votes the right way when it doesn’t count and the wrong way when it does,” said Hay Bright, faulting Snowe’s opposition to a federal minimum wage increase and support of the confirmation of Supreme Court Justice Samuel Alito, whose judicial record has raised concerns among abortion rights supporters.

After her Thursday speech, Snowe defended her voting record and her centrist credentials.

“If anything, we need more consensus builders rather than the partisan attacks that have been the way of life in Washington,” said Snowe, who also opposed the Bush administration’s plan to open the Arctic National Wildlife Refuge to oil drilling.

While Snowe might be a heavy favorite, political upsets of popular incumbents are not unprecedented in Maine. Such was the case in 1972, when William Hathaway ended the career of U.S. Sen. Margaret Chase Smith.

Snowe on Thursday said she is taking nothing for granted.

“I have great respect for the ballot,” she said during her stop in Portland. “You never know what’s going to happen.”

The Associated Press contributed to this report.