AUGUSTA, Maine — The first public poll conducted on Maine’s now-wide-open U.S. Senate race showed independent Angus King with an edge in a hypothetical three-way matchup against Democrat Chellie Pingree and Republican Charlie Summers.

A Public Policy Polling survey of 1,256 Maine voters conducted over the weekend also showed King — who announced Monday that he’s officially in the race — as the most popular of any of the potential candidates. The two-term governor’s favorability rating was 62 percent compared with an unfavorability rating of 24 percent.

Pingree and Summers both had lower favorables and higher unfavorables than King, but it’s important to stress that, while they are the front-runners, neither Pingree nor Summers are their party’s nominee.

It’s also worth noting that the PPP survey skewed slightly Democratic. Of those polled, 43 percent identified themselves as Democrats, 34 percent as Republicans and 23 percent as unenrolled. The poll also had a margin of error of plus or minus 2.8 percent.

There has been enormous interest in the U.S. Senate race in Maine since Olympia Snowe announced she would not seek a fourth term. The flurry of activity in the days that followed prompted PPP to conduct its poll.

Among the three-dozen questions asked, perhaps the most intriguing was: “If the candidates for U.S. Senate this fall were Republican Charlie Summers, Democrat Chellie Pingree, and independent Angus King, who would you vote for?”

King received 36 percent support, followed by Pingree with 31 percent and Summers with 28 percent. In that scenario, King was supported by 53 percent of independents, 35 percent of Democrats, and 25 percent of Republicans.

Those who supported King in the poll also preferred that if he is elected, he caucus with the Senate Democrats. In an interview Tuesday, he said it is much too early to divulge which party he’d caucus with.

“Angus King and Chellie Pingree look like the early favorites in Maine,” said Dean Debnam, President of Public Policy Polling. “King will have a hard time holding onto his early Democratic support without a pledge to caucus with the party if he’s elected to the Senate.”

Pingree had the most support among Democrats, with 52 percent, followed by former Gov. John Baldacci at 28 percent and former Secretary of State Matthew Dunlap at 11 percent. Baldacci had the highest unfavorability rating (52 percent) of any potential candidate polled.

Some have speculated that King’s entrance into the Senate race might prompt Pingree to stay put in the 1st District, where she likely would be reelected. Pingree, as of Tuesday, had not made up her mind.

On the Republican side, PPP concluded that the field of candidates was weak based on low name-recognition.

Among those polled, Peter Cianchette received the most support with 21 percent, but he isn’t even running.

Summers, the current secretary of state and a 2008 U.S. House candidate, was second at 18 percent, followed by Scott D’Amboise (10 percent), former Maine Senate President Rick Bennett (9 percent) and state Treasurer Bruce Poliquin (8 percent).

Attorney General William Schneider, who some feel could be the GOP front-runner, got only 1 percent support. Assistant Senate Majority Leader Debra Plowman of Hampden, who is gathering signatures to run for the Senate, received 4 percent support.

Poliquin, the former gubernatorial candidate who has turned the treasurer’s office into a high-profile position, had decent name-recognition compared to other GOP candidates but he also had the highest unfavorability rating (40 percent).

If King were not in the race, Pingree also would lead head-to-head matchups against any of the Republican hopefuls by an average of 16 points, the poll found. Baldacci also leads over GOP hopefuls, but only by an average of eight points.

Party candidates have until March 15 to gather 2,000 signatures in order to officially get into the Senate race. Independent candidates have until June but must submit 4,000 signatures.