Because Oahu has a population of more than 1 million people, each of the nine Honolulu City Council members represents more than 100,000 constituents.

That makes Council members among the most influential and high-profile elected officials in the state. Besides decisions on nuts-and-bolts issues from property taxes and city roads to parks and garbage pickup, they set policies on weighty issues such as homelessness, housing, land development and zoning laws, sea level rise and, yes, the now partially completed $8.2 billion rail project.

Campaign financing reports reflect this, as winning candidates commonly spend more than $100,000 to win.

The Council also provides the natural counterpoint to the Hono­lulu mayor. In recent years there’ve been two factions — one led by Council Chairman Ernie Martin, which has been more acerbic with Mayor Kirk Caldwell and his policies, and a second, led most recently by Councilman Ron Menor, which has been generally friendlier to the administration. Who wins this fall will determine who leads the Council and likely how far Caldwell can advance his agenda in his last two years as mayor.

This year four Council seats are up for grabs. Martin was not eligible for re-election since no one can serve more than two consecutive terms. That leaves the District 2 race wide open for a new member, and an intriguing field of candidates has emerged.

But don’t go to sleep on the three other Council races, which also feature viable challenges to the re-election hopes of incumbents Brandon Elefante, Carol Fukunaga and Trevor Ozawa.

Honolulu’s runoff-style election process allows a candidate for Council to walk away with the seat outright in the Aug. 11 primary election.

To win outright, a candidate must garner more than 50 percent of actual votes cast, so blank votes are not factored into the percentages. Otherwise, the top two candidates advance to a one-on-one contest on Nov. 6. Races featuring only two candidates bypass the primary and automatically proceed to the November election.

District 2

(Mililani Mauka to Kahaluu)

With no incumbent, more campaign money has been pumped into the District 2 race than any of the other three.

Most of the money is going to former state Sen. Robert Bunda, once the Senate president, and Heidi Tsuneyoshi, an aide to Martin who has the support of her boss and others in his Council faction. In a campaign that features television ads, Bunda has so far spent $133,000 while Tsuneyoshi has spent $87,000, according to reports filed with the state Campaign Spending Commission. Both still had sizable war chests as of June 30, with Bunda reporting $175,000 cash on hand and Tsuneyoshi reporting $139,000.

Bunda is touting his experience with 28 years in the Legislature, including six as Senate president, as a key selling point. But he hasn’t held elected office since 2010, and Tsuneyoshi is calling herself part of “a new generation of leadership.”

Realtor and community advocate Choon James and farmer Dave Burlew, who ran against Martin in 2014, are also hoping to capture the seat. James, who’s running on a “Residents First” campaign, is refusing to take contributions from big-money interests and is largely self-financing her campaign. Burlew, who has filed no campaign spending report because he has declared he is spending less than $1,000, has adopted “Country on the Council” as his theme and is stressing rural preservation as a top priority.

District 4

(Hawaii Kai to Ala Moana Park)

The three top finishers in the 2014 election return for a rematch. Ozawa, an attorney, beat attorney and former state Rep. Tommy Waters by a mere 41 votes with 4,455 blank votes in 2014. Waters had finished first ahead of Ozawa by nearly 2,100 votes in the four-person primary election that August.

CPA and community advocate Natalie Iwasa, known as “Bike Mom” around Honolulu Hale because of her efforts to make Oahu more bike-friendly, is also challenging Ozawa this year. Iwasa finished with a sizable 6,937 votes, only 1,075 votes behind Ozawa.

Ozawa had spent about $176,000 on his re-election bid as of June 30, far outpacing Waters’ $19,900 spent. Iwasa has spent $5,100. Ozawa reported having $251,500 left in his bank account, while Waters reported $49,500 and Iwasa reported $11,000.

Also in the race is Ricky Marumoto, an assistant golf professional at Honolulu Country Club.

Ozawa is a key ally of Martin’s and was selected to chair the powerful Council Budget Committee earlier this year. Waters was considered an ally of Caldwell’s when both served in the state House of Representatives in the early 2000s.

District 6

(Makiki to Kalihi)

Fukunaga is facing challenges from Hawaii Construction Alliance official Tyler Dos Santos-Tam, community advocate and magazine publisher Ikaika Hussey and political newcomer Zack Stoddard.

Dos Santos-Tam, making his first bid at elective office, out-raised and out-spent Fukunaga. He’s raised $143,000 to Fukunaga’s $141,000 while Hussey has raised $24,000. Dos Santos-Tam has spent $113,000 to Fukunaga’s $56,000 and Hussey’s $24,000.

Fukunaga reported more available, $47,000 on June 30, than Dos Santos-Tam ($32,000) and Hussey (negative $360).

Before her election to the Council in 2012, Fukunaga spent 30 years at the Legislature and at one time co-chaired the Senate Ways and Means Committee. She has a reputation as a tireless advocate for her district.

While Fukunaga is considered a part of the Martin faction of the Council, she’s been known to work with Caldwell on occasion.

Dos Santos-Tam’s position with the Hawaii Construction Alliance assured him the support of several key unions.

Hussey, whose wife is Sierra Club of Hawaii Executive Director Marti Townsend, has won endorsements from progressive organizations including the Oahu chapter of Our Revolution, the organization started by Bernie Sanders.

Stoddard is an employee with the city Department of Planning and Permitting. He reported raising and spending $775. On his web page he describes himself as “just a regular guy making a modest city worker’s salary that wants to make a change.”

District 8

(Lower Aiea to Waipahu)

Elefante has a single challenger in Kelly Kitashima, a hotel executive who was Mrs. Hawaii 2016 and is making her first run at elected office.

When there are two candidates for a Council race, the candidates face off in a single election in November under the City Charter. So the District 8 election will not be on the Aug. 11 ballot.

Martin held a meet-and-greet in Waimalu with Kitashima on Tuesday night. Elefante is regarded as an independent thinker who tends to side with Caldwell rather than the Council chairman on political issues.

As of June 30, Elefante reported $83,000 in contributions, $55,000 spent and a cash balance of $36,000. Kitashima reported $24,000 in contributions, $12,000 in expenditures and a cash balance of $12,000.