The gallery of a DuPage County courtroom erupted in a round of applause and a standing ovation Wednesday when a judge dismissed disorderly conduct charges against a pair of war protesters arrested last year for displaying a sign above a local toll road.

Jeff Zurawski, 40, of Downers Grove and Sarah Hartfield, 46, of Naperville were set to stand trial, but the prosecution’s key witness failed to appear to testify. Assistant state’s attorney Johnetta Sanks asked Judge Ronald Sutter to dismiss the case due to lack of evidence.

“That’s one way to win a case,” defense attorney Shawn Collins said outside the courtroom to a crowd of about 50 supporters who attended the trial. “The objective, I always felt, was to win. I would have preferred to confront the evidence because I think it was weak.”

Zurawski and Hartfield were arrested in May 2007, a few weeks after displaying a sign that read, “Impeach Bush and Cheney — Liars,” and an upside American flag on the Great Western Trail bridge over Interstate 355. Prosecutors had alleged that one of the two made a throwing motion toward the highway but later amended the charges to say they caused a disturbance to drivers by displaying the sign.

Charles Hardin, a trucker who was driving on the highway on May 6, 2007, called 911 to report what he said appeared to be “two youths” throwing things toward the road.

Hardin previously testified at a hearing in April, after which Sutter ruled that sheriff’s deputies had probable cause in arresting the protesters. Hardin told the judge that although he didn’t see Hartfield or Zurawski make any kind of throwing motion, traffic had “slowed to a crawl” as cars tried to move out of the center lane.

Hardin was expected to testify at the Wednesday bench trial, but he did not show up at the Wheaton courthouse. Sutter gave prosecutors a few extra minutes to see if he would arrive but dismissed the charges when he was not there about half an hour after the trial was scheduled to begin.

Outside the courtroom, Zurawski told supporters he was relieved, but he wished the case never happened.

“Having been wrapped up in this so long, having been lead away from my home in handcuffs after doing nothing more than express my opinion, it still burns a little,” he said.

Zurawski said the experience will not deter him from continuing to express his opinions in public. He may even once again bring out the sign that lead to his arrest, he said.

In thanking their supporters, a tearful Hartfield said she was crying “tears of joy and sorrow.”

Zurawksi, Hartfield and their supporters contend that they were charged because sheriff’s deputies and prosecutors did not like their message.

DuPage County State’s Attorney Joe Birkett said it was the venue, not the message, that lead to the arrest.

“You can’t shout fire in a crowded theater, and you can’t hang a homemade banner over a highway where people are driving 65 or 70 mph,” Birkett said in an interview following the dismissal.