Schatz, who has the backing of the Democratic Senatorial Campaign Committee and most Senate Democrats, got a boost from Senate Majority Whip Dick DurbinRichard (Dick) Joseph DurbinGOP leaders to Trump: Leave Mueller alone Water has experienced a decade of bipartisan success Trump vows tougher borders to fight opioid epidemic MORE (D-Ill.).

Hanabusa's event was headlined by Irene Inouye, the widow of former Sen. Daniel Inouye (D-Hawaii). The former senator's dying request was for Hanabusa to be named to his seat, but Hawaii Gov. Neil Abercrombie (D) chose Schatz instead, leading to the testy primary.

Schatz has the early leg up in fundraising, with $1.6 million in the bank to Hanabusa's $650,000.