Rep. Bernie Sanders (search) holds commanding leads over two possible Republican candidates in the race to replace Sen. Jim Jeffords (search), a new poll shows.

The poll, conducted by Rockville, Md.-based Research 2000 for WCAX-TV, was the first since Jeffords, an independent, announced last month he would not seek a fourth term next year.

Sanders, the state's only congressman and the only independent in the House, has all but declared himself a candidate. Like Jeffords, Sanders votes with the Democrats.

He was picked by 59 percent of respondents in a matchup against Lt. Gov. Brian Dubie (search), a Republican who was favored by 23 percent, according to the poll results released Monday.

Sixty-two percent of respondents said they would vote for Sanders in a race against businessman Richard Tarrant (search), also a Republican. He was favored by 18 percent of respondents.

In the poll, 66 percent had a favorable opinion of Sanders, who has served in the House since 1991. Roughly a quarter had an unfavorable opinion and 7 percent had no opinion.

Dubie, who has served as lieutenant governor for three years, had a favorability rating of 37 percent, while 18 percent had an unfavorable opinion and nearly half had no opinion. Eighty-five percent of those surveyed said they had no opinion of Tarrant, who is the founder and chairman of health care software company IDX (search) and has never held elective office.

The poll did not include any Democratic candidates. In recent years, the Democrats have not fielded a candidate against Sanders in his congressional races.

Jeffords quit the Republican Party four years ago because of disagreements with the Bush administration. That move, and his decision to caucus with the Democrats, put Democrats in charge of the Senate. The GOP regained power after the 2002 elections.

The telephone poll of 400 likely voters was conducted between May 4 and Saturday. The poll had a margin of error of plus or minus 5 percentage points.