U.S. Sen. Brian Schatz has expanded his fundraising edge over U.S. Rep. Colleen Hanabusa in their Democratic primary for U.S. Senate, as Hanabusa struggled through a subpar quarter.

Schatz raised more than $677,900 from July through September, according to a draft of his campaign finance report, and has brought in $2.7 million overall. Hanabusa raised more than $440,800 for the quarter and has brought in $1.1 million, her campaign announced, including money transferred from her House account.

The third quarter in a non-election year often presents a fundraising challenge for Hawaii political candidates, who have to compete for donors during summer months when politics is not top-of-mind and the primary is a year away. Neither Schatz nor Hanabusa has ever had to raise the $3 million to $5 million necessary for a premier statewide campaign, so they are not accustomed to the constant pressure to raise money and meet expectations every quarter.

Schatz’s mark was down significantly from the $911,000 the appointed senator posted in July and the $1 million he opened with in April.

But Hanabusa is in a more complicated position. Her campaign advisers said earlier this year that there was a pent-up demand of financial support for the congresswoman that would be revealed once she formally announced her campaign. In July, after raising $500,000, campaign advisers said Hanabusa did not really have a full quarter since she had only declared in May.

In September, the Hanabusa campaign warned supporters that if the congresswoman did not meet her fundraising target the campaign may have to scale back field operations, a message campaign insiders acknowledge was a public-relations mistake.

Her underwhelming fundraising numbers will likely have little influence on the average primary voter, who rarely pays much attention to the quarterly money chase. But the relatively low mark could be damaging to the Hanabusa campaign in national and local political circles, where metrics such as fundraising and endorsements are critical measures of viability.

Earlier this month, The Fix, the Washington Post’s political blog, identified the Schatz-Hanabusa primary as among the top 10 nationally next year. Roll Call, a newspaper that covers Capitol Hill, listed Hanabusa’s quarterly fundraising report as among the five to watch for the Senate.

"It’s clear that Sen. Schatz has put together a superior campaign organization. His impressive fundraising and endorsements are indicators of that," Matt Canter, a spokesman for the Democratic Senatorial Campaign Committee, which supports Schatz, said in an email.

NEAL Milner, a University of Hawaii at Manoa professor emeritus of political science, said Hanabusa might need a good explanation given that fundraising is routinely used to judge the strength of a campaign.

"It may not be a reliable indicator, but it is certainly an indicator that people who pay close attention to politics and people who are supporters already of one candidate or another take seriously," Milner said. "So they look at something like this and I think the obvious question for the Hanabusa supporters is, ‘How come?’"

Cameron Nekota, the chairman of Hanabusa’s campaign, said the campaign does not measure success by fundraising totals.

"We are thankful for our supporters’ help with keeping our campaign well financed and allowing Colleen to reach out to the community, but fundraising totals are not how we measure success," he said in a statement. "The outpouring of support from across the state letting us know that the people of Hawaii want a proven, experienced leader in the U.S. Senate continues to impress us and has helped define our campaign."

Clay Schroers, Schatz’s campaign manager, said support for the senator is growing. "As the people of Hawaii see the work Sen. Schatz is doing to create jobs, expand Hawaii’s clean energy economy, and stand up for middle-class families through his efforts promoting equal pay for equal work, the more support for Sen. Schatz continues to grow," he said in a statement.

The August primary between Schatz and Hanabusa is to select the party’s candidate to fill out the remainder of the late U.S. Sen. Daniel Inouye’s six-year term, which runs through 2016. Cam Cavasso, a former state lawmaker, is the only Republican who has signaled a campaign.