King has not said with which party he would caucus if elected to the Senate, though most observers expect he will choose to join Senate Democrats. The Democratic Senatorial Campaign Committee notably neglected to mention Dill's victory last week, and King's performance among the state's likely Democratic voters in the poll further reflects the widespread belief he will support their party. If King continues to be considered the de facto Democratic candidate, he can expect to be buoyed by the top of the ticket: The poll shows President Obama leading Mitt Romney in the state, 48 percent to 34 percent. King may also fit the mold of the state's two moderate Republican senators, who are extremely popular in the state. Both Snowe and Sen. Susan Collins sport favorablity ratings of 80 percent or higher, with the percentages of likely voters who have unfavorable opinions of them in the single digits. In order for Summers to overtake King, he needs Dill to cut into King's lead among Democrats. But Summers would also be advised to align himself with Snowe and Collins rather than first-term GOP Gov. Paul LePage. Fully half of voters have an unfavorable opinion of LePage, and a plurality of voters disapprove of the job he is doing as governor. The poll was conducted by Boston-based MassINC Polling Group. Likely voters were interviewed on June 13 and 14 -- the two days immediately following last week's primaries. MassINC interviewed 506 likely voters via landline and cellular telephone, for a margin of error of plus-or-minus 4.4 percentage points.