U.S. Sen. Susan Collins, R-Maine, in 2019, left, and Maine House Speaker and Senate contender Sara Gideon, D-Freeport, right. Credit: File / AP

A poll released Monday showed House Speaker Sara Gideon with a narrow lead over Sen. Susan Collins, with the Democrat receiving 46 percent support compared with 42 percent for the Republican incumbent.

The poll of more than 1,000 Maine voters conducted July 2 and 3 had a margin of error of 3.1 percent. Its margin is similar to that of a March poll released by Public Policy Polling, a North Carolina-based firm that typically polls for Democrats. It is the third straight public poll showing Gideon with a slight lead over Collins, who was the leader in early polls last year.

Earlier polling has pegged Gideon as the favorite in a July 14 primary with lobbyist Betsy Sweet and lawyer Bre Kidman. She is backed by national Democrats while Sweet has picked up endorsements from several progressive groups. Kidman has run a nontraditional campaign, focusing on aiding the coronavirus response over the past few months.

Both the primary and the general election will be decided by ranked-choice voting. Several independents, including former Green candidate Lisa Savage and conservative Max Linn, will likely be on the ballot.

The poll released on Monday found Collins’ approval rating held roughly steady with 36 percent of voters approving of her performance as senator, while 55 percent disapproved. That is roughly on par with polling over the last six months, but significantly down from her approval rating when Trump took office in 2017, when the firm Morning Consult found 67 percent of voters approved of her while only 27 percent disapproved.

Support for Collins, who has been re-elected easily in the past with a coalition including many independents and Democrats, largely fell along partisan lines. Only 13 percent of Democrats approved of the incumbent Republican, while 63 percent of Republicans approved of Collins.

Among independents, 39 percent approved of Collins, while 50 percent disapproved. Forty-five percent of independents characterized Collins as an “independent voice,” while 46 percent characterized the senator as more partisan.

Gideon’s favorability numbers were even, with 37 percent of voters holding a favorable opinion of her and 37 percent holding an unfavorable one. Another 26 percent had no opinion of her, showing she has yet to be fully defined for the electorate. Among independents, 34 percent held a favorable opinion of the House speaker, while 33 percent held an unfavorable opinion.

Collins is one of national Democrats’ top targets in 2020 as the party looks to take back control of the U.S. Senate. The race has seen record fundraising from both the incumbent and Gideon, as well as more than $13 million in independent expenditure spending and millions more from dark-money groups.

The poll released Monday also found former Vice President Joe Biden, the presumptive Democratic presidential nominee, with an 11-point lead over President Donald Trump in a head-to-head matchup, with 5 percent undecided. In 2016, Hillary Clinton won Maine by only 3 points, while losing the 2nd Congressional District by 10 points. The poll did not break down results by district.

Forty-one percent of voters said they approved of Trump’s performance, while 55 percent disapproved. Those figures are similar to current national averages, according to FiveThirtyEight.

Nearly a third of voters cited jobs and the economy as their most important electoral issue, while almost an equal percentage said handling of the coronavirus was the most important. Health care was the third most-cited issue, with 17 percent of voters saying they cared about it most.