MADISON, Wis. — A pedestrian bridge over Interstate 90 has linked the two sides of a western Wisconsin burg for decades, providing a test of courage for bike-riding children and a symbol of home for travelers returning from Minnesota.

Over the last year, the town of Campbell’s overpass has become the front line in a Hatfield vs. McCoy free-speech clash between a tea party activist and the police chief.

The fight was spurred by last summer’s national push for tea party overpass protests calling for President Barack Obama’s impeachment. Nowhere, though, has the protest caused as much of an uproar as in Campbell.

The local tea party alleges the town and Police Chief Tim Kelemen are trying to curtail their free-speech rights by banning signs on the overpass. The chief, for his part, maintains tea party supporters responded to the ordinance by deluging his agency with complaints and threats. So, he fought back by registering one of the party’s leading activists with websites for gay dating, pornographic and federal health care.

Now Keleman could lose his job and possibly face criminal charges.

“This reaction by a public officer, I don’t know how to describe it. Just extremely unfortunate and poor decision-making,” said Erin Mersino, attorney for local tea party leader Greg Luce.

Keleman’s lawyer, Jim Birnbaum, counters that the tea party pushed his client to the edge.

“There’s a major difference between an exercise of poor judgment and a crime,” Birnbaum said. “They’re under fire with threats. The tea party invited the wolves out of the forest.”

Campbell, home to about 4,000 people, is just outside La Crosse on French Island in the Mississippi River. I-90 bifurcates the town; the overpass allows pedestrians to cross from one side to the other.

La Crosse Tea Party members held at least five protests on the overpass between August and October, according to court documents. Kelemen noticed interstate traffic slowed in response to the protesters’ signs and banners. Concerned the protests were creating a safety hazard, he convinced the town board to pass an ordinance in October banning signs, banners and flags on the bridge.

Tea party supporters flooded the five-officer department with complaints; some threatened the officers with death, according to Kelemen’s records. Someone also tried to hack into his personal bank accounts and a department computer, the chief said.

Kelemen said he asked the state Department of Justice for help, but the agency only offered to upgrade firewalls. DOJ spokeswoman Dana Brueck said the agency focuses on problems of statewide importance.

In January, Luce mysteriously began receiving calls and emails from the gay dating, porn and health care websites, according to police reports and court documents. La Crosse investigators tracked some of the activity to a computer at Kelemen’s home and the Campbell town hall, according to an incident report.

Given Kelemen’s close relationship with La Crosse officers, the department asked DOJ to take the case but the agency refused. It landed in the hands of the neighboring Monroe County Sheriff’s Department.

An investigator from that agency interviewed Kelemen in May. The chief initially said he knew nothing about the websites. Later, though, he acknowledged he signed Luce up for the sites in retaliation for the harassment.

He said he believed Luce told people to bother the department, according to the detective’s report, and he felt helpless because DOJ wouldn’t investigate Luce.

“I’m like, all right, buddy, you cause us a hassle, we’re going to cause you a hassle,” Kelemen said in a video of the interview the La Crosse tea party posted on YouTube.

“I was a really heavy Republican kind of guy,” he added later. “I kind of agreed with all these things that they were saying. (But) now I see how these guys operate and that’s super shady.”

Birnbaum, who says Kelemen now considers himself an independent, wouldn’t confirm the video’s authenticity, saying he hadn’t seen it. Investigator Jeff Spencer referred questions to La Crosse police; a message left with that agency wasn’t returned.

Luce has sued Keleman and the town in federal court, alleging Kelemen stole his identity and that the overpass ordinance violates his free-speech rights.

The town board placed Kelemen on paid leave this month. Board Chairman Scott Johnson didn’t return multiple messages. Monroe County District Attorney Kevin Croninger said he’s close to making a decision on charges but declined to elaborate.

Mersino said Luce is simply upset with the sign ordinance and never asked anyone to threaten officers.

“A person can’t justify illegal behavior of identity theft,” she said, “by saying they received a few annoying phone calls to the police station.”