Jackson County legislator. It’s just a $25,900-a-year job.

But this year, the political campaigns ahead of the Aug. 3 primaries for the Legislature are proving surprisingly hard-fought and big-moneyed.

Candidates themselves are investing tens of thousands of dollars in campaigns already attracting significant contributions from local unions, businesses and political backers such as James B. Nutter Sr.

Candidates have accused each other of dirty tricks and warping the truth as they joust with TV spots, billboards and mailers weeks before the voting. Such expensive campaigns usually have been reserved for quests for City Hall or statewide races.

“It’s a county race and we’ve got candidates with TV ads weeks before the vote,” said Steve Glorioso, a political consultant who has helped candidate Dennis Waits in his quest to stay on the Legislature. “I can’t remember that — ever.”

Longtime county political observers point to a number of factors that are heating up the political runs for the county courthouse:

•New interest and money are flowing into the campaigns from influential unions that now represent assistant prosecutors and other county employees.

•Term limits have pushed some candidates into county races.

•Stephen Bough, chairman of the Jackson County Democratic Party, said serving on the Legislature had benefits for a Kansas City politico.

“It’s attractive because it’s local and it comes with a nice paycheck,” he said. Also, “it’s not tough duty.”

It doesn’t require a lot of time and the compensation can be much greater than the $25,900 salary.

Every budget year, each legislator is allotted about $90,000 to run his or her office. From that, each can pay for a car allowance (some have taken $7,000), phone and other expenses, as well as an aide’s salary. There are health benefits and a pension, too.

The ferocity of the Legislature battles this year might best be exemplified in the race for the 3rd District at-large slot, pitting incumbent Fred Arbanas against Terry Riley, who can’t run for re-election to the Kansas City Council because of term limits.

Arbanas, a retired Chiefs tight end, has held an elected post since the Legislature was created in 1973, making him the longest-serving elected official in the county, if not Missouri. Arbanas has already invested $70,000 of his own money in his campaign. He is out every day, he said, attending meetings and asking for votes.

“There have never been any races in the Jackson County Legislature like this before, never before,” Arbanas said. “I’ve never had an opponent this formidable. … It’s got me up and campaigning hard.”

Riley said he was also surprised at the hard nature of the race so far.

“These races are historic,” Riley said, “because many of these guys have never been challenged.”

Riley last week filed a complaint against Arbanas, alleging that county taxpayer funds had illegally been used to pay for a county TV ad promoting parks. A guest appearance by Arbanas gives him a campaign advantage, Riley said.

Arbanas has since asked the county to pull the ad.

Meanwhile, Arbanas has accused Riley of stretching the truth in campaign mailers that have accused Arbanas of raising sales taxes (when a vote is actually required).

Some Arbanas supporters also have noted that Riley’s promotions carry a shamrock, even though Riley, who is African-American, stakes no claim to being Irish.

“This is hysterical,” Riley said. “I used shamrocks four years ago (in a successful re-election bid for the council), and no one said anything.”

According to the most recent campaign fundraising reports, Arbanas has raised more than $90,000 and has $56,500 on hand. Among his supporters are the Kansas City Chiefs and other former football players.

Riley reported raising $27,715, which includes a $5,000 contribution from Burns & McDonnell, the engineering giant that has regularly financed campaigns for City Hall, where Riley is chairman of the council’s Transportation and Infrastructure Committee.

In the 2006 Democratic primaries, only one legislator, Scott Burnett, had a significant challenge. On the Republican side, Greg Grounds, a former Blue Springs mayor, unseated incumbent Rhonda Shoemaker. But the other races were pretty uneventful.

In these primaries, however, up to four Democratic incumbents face interesting challenges.

Waits, who has served since 1986, faces Curt Dougherty, who has represented the 53rd District in the Missouri General Assembly, but can’t seek re-election because of term limits.

Theresa Garza Ruiz, who won election in 2006, faces Ray Salva Jr., making his first bid for political office.

And the Legislature’s chairman, Henry Rizzo, backed by Local 42 of the International Association of Fire Fighters, faces Crystal Williams, who earlier had to battle in court to remove from the ballot an opponent who claimed her name was Diane “Crystal” Williams. That woman withdrew from the race the day before sworn depositions were scheduled.

(Rizzo has denied any connection with Diane Williams.)

Meanwhile, Crystal Williams last week launched the first TV ad in the campaign, while union supporters have blanketed frequent voters with Rizzo promotions.

A third candidate on the ballot in the 2nd District at-large race, Patricia Flucas, has declined to participate in any candidate surveys and has not returned phone calls.

In Republican races, incumbent Bob Spence is challenged by Joseph Spallo, a Lee’s Summit councilman since 1995. Grounds faces newcomers Pat Bottcher of Grain Valley and Jay Still of Independence.