Incumbent Sen. Brian SchatzBrian Emanuel SchatzDem senator: 'Stop pretending' law banning separation of migrant families is hard to pass Hillicon Valley: Judge approves AT&T-Time Warner deal in blow to DOJ | Dems renew push to secure state voting systems | Seattle reverses course on tax after Amazon backlash | Trump, senators headed for cyber clash | More Tesla layoffs Dems question FCC's claim of cyberattack during net neutrality comment period MORE (D-Hawaii) leads his Democratic challenger Rep. Colleen HanabusaColleen Wakako HanabusaOvernight Energy: Zinke defends ‘Konichiwa’ greeting | Lowe's drops cancer-linked chemical from stores | Fight between EPA, Dem over summit heats up Zinke cites ‘friends that were Japanese’ in defending 'konichiwa' greeting West Virginians thankfully rejected Don Blankenship's racist remarks MORE (D-Hawaii) by 5 percentage points, according to a new poll.

A Civil Beat Poll released Tuesday found 44 percent of Hawaii voters support Schatz, while 39 percent said they’d vote for Hanabusa. Sixteen percent said they’re undecided.

This is the fourth poll Civil Beat has conducted for this race, but the first one in which one candidate has gained a slight advantage, Civil Beat said. Previous surveys suggested the race was tied.

A recent survey conducted by Public Policy Polling for Democracy for American, a group that backs Schatz, indicated he led Hanabusa by 15 percentage points.

Both lawmakers are competing for the Democratic nomination in the Aug. 9 primary. President Obama has endorsed Schatz.

Hawaii Gov. Neil Abercrombie (D) appointed Schatz to the Senate in late 2012, after Sen. Daniel Inouye died.

Abercrombie reportedly received a “dying wish” from Inouye, just after he died, urging him to appoint Hanabusa as his successor. She was elected to the House in 2010. 

The latest Civil Beat poll surveyed 840 registered Hawaii voters May 18 to 19 with a 4.3 percent margin of error.