A lawsuit against the United States government and a former federal probation officer for sexual assault includes multiple accusers, phone recordings and pornographic e-mails sent by the accused, according to the women's attorney.

Yet the women who filed the suit face a legal obstacle that has nothing to do with the evidence.

A federal judge has twice dismissed the case, despite the government's attorneys never once arguing that the former probation officer, Dennis Bresnahan, was innocent.

As an employee of the United States, Bresnahan's position confers a powerful immunity. Federal law shields the U.S. government from lawsuits if one of its former employees is accused of sexual and physical assault on the job, with only a few exceptions.

"I don't think the public realizes the uphill battle that victims face," said the women's attorney, Kenneth Udoibok.

A University of St. Thomas law professor is hoping to change that. Earlier this year, Gregory Sisk published a paper revealing the immunity that the government holds, and argued that without legislative reform, victims assaulted by federal employees will not have the opportunity to hold the perpetrators liable in civil court.

As an example, Sisk brought up a 2003 case of an Illinois postal worker who had been accused of sexually abusing nine girls along his route and earned the nickname "Lester the molester" by his co-workers.

After a judge found him guilty, the children's parents filed suit against the postal service. But those cases were dismissed because of the immunity enjoyed by the U.S. government, Sisk said.

"We need to get rid of that exception," Sisk said.

That immunity dates back to the 1946. Before that, no one could bring a lawsuit against the U.S. government. Instead, Congress had to convene an inquiry if someone filed an injury complaint, Sisk said.

To make the process easier, Congress created an exception that allowed government lawsuits in common injury cases, such as car accidents. But assaults were exempt. In 1974, Congress allowed an exception to sue law enforcement accused of assault.

That's how the lawsuit against Bresnahan survives today. After filing the suit in September 2017, the judge in the case, Robert Pratt, dismissed two of the complaints filed, both times citing the federal immunity.

But each time, Pratt gave the women another chance to refile their suit. On the third attempt, their attorney, Udoibok, argued that Bresnahan was acting in his duty as a law enforcement officer. He also argued that the government should have known that probation officers can use their authority to assault the people they supervise.

Bresnahan, through his attorney, has denied the assaults. In March, he pleaded guilty to two counts of lying to the FBI in a criminal case related to the assault allegations.

In January, Pratt sided with the women. A trial has been set for October.

As he stood with the women at a meeting in March, Udoibok reminded them just how difficult it will be to win the case. "I've said before that to even have a 10 percent chance, we need to do everything 100 percent right," he told them.

The women said they were disappointed that Bresnahan didn't plead guilty to more serious charges and hope the civil case brings them justice.

"I hope [Bresnahan] understands the impact of what he's done to us and other women. That he understands the pain," said one of the women, Tammy Bloomer.

The attorney representing the U.S. government in the case declined to comment.

As for Sisk, he said he's lobbied several senators on scrapping the exemption, but thus far hasn't seen a significant response.

"The United States should be no less accountable for sexual violence by its employees than any other employer," Sisk said.