Rep. Bill Janklow (search) on Monday announced he would resign from the House after a jury convicted him of all charges in the traffic death of a motorcyclist.

Janklow also faces a possible jail term for the charge of second-degree manslaughter.

"I wish to inform you that because of present circumstances, I will be unable to perform the duties incumbent on me in representing the people of South Dakota as their U.S. representative," Janklow wrote in a letter that he said was to be sent to House Speaker Dennis Hastert (search) on Tuesday.

"Therefore I wish to inform you that I will resign from the House of Representatives, effective January 20, 2004."

A fixture in South Dakota politics for 30 years, Janklow's resignation coincides with the day he will be sentenced.

Raw Data: South Dakota v. Janklow (pdf)

The congressman seemed stunned when the verdict was read after a five-hour deliberation Monday evening. He walked out of the courtroom, got in a vehicle driven by his son and left the courthouse without uttering a word to a horde of reporters.

Janklow had argued that a diabetic reaction was responsible for the fatal crash — a defense his hometown jury did not buy.

Janklow, 64, was convicted of second-degree manslaughter, reckless driving, running a stop sign and speeding for the Aug. 16 crash that killed Randy Scott (search), 55, a farmer from Hardwick, Minn. Prosecutors said Janklow was traveling more than 70 mph in his white Cadillac when he crashed with Scott's Harley-Davidson.

"The state of South Dakota brought charges against a man we believed to be responsible for Randy's death," the victim's mother, Marcella Scott, said in a statement. "We are satisfied that the correct verdict was reached."

Jurors left the courthouse without talking to reporters. They were escorted out by the sheriff, who said the jurors don't want to talk to the media. Both prosecutor Bill Ellingson and defense attorney Ed Evans refused comment.

A special election will be held during South Dakota's June 1 primary to fill the remainder of Janklow's term, giving Democrats an early chance to pick up a seat in the narrowly divided House. Janklow would have been up for re-election next November.

By stepping down, Janklow avoided an ethics investigation in the House. The ethics committee could have recommended a resolution reprimanding Janklow, censuring him or even expelling him, though the House rarely takes that last step.

Janklow's trial created a scenario that once would have seemed unthinkable in this rural state: a congressman on trial for manslaughter in the farming community where he grew up.

The trial began Dec. 1 with a jury-selection process that revealed Janklow's widespread popularity in Flandreau, a town of about 2,000 people. Several jury candidates knew Janklow and his family, including one who shook hands with the former governor as he left the courtroom.

Once a panel was chosen, jurors witnessed several emotional images during five days of testimony, including Janklow in tears as he described his grief over the crash. A man who was riding motorcycles with Scott cried as he recalled finding the victim's mangled body in a soybean field. Senate Democratic Leader Tom Daschle (search), himself a pillar of South Dakota politics, also took the stand.

The defense argued that Janklow, a diabetic, was suffering the effects of low blood sugar at the time of the crash because he had not eaten for 18 hours. Medical experts told prosecutors it is unusual for anyone to go that long without food -- and highly dangerous for a diabetic who takes insulin.

But deputy prosecutor Roger Ellyson called the diabetes defense "goofy," saying Janklow concocted the defense as an excuse for his reckless driving.

Ellyson called Janklow an "unbelievably awful and menacing" driver.

"The defendant's driving is like a deadly game of Russian roulette," Ellyson said in closing arguments. "On August 16, Randy Scott took the bullet."

"He couldn't say, 'I was driving so fast I couldn't stop.' Or he couldn't say, 'I always ignore these rural stop signs.' That would be admitting to manslaughter. He knows the trouble he's in," Ellyson said.

The defense said that Janklow took heart medication on the day of the crash that can mask the symptoms of a diabetic reaction. That is why Janklow did not feel his blood sugar drop before the accident, the defense contended.

Several witnesses said they did not see Janklow eat or drink anything that day, including Daschle, who called the congressman "a very truthful person."

Janklow has long been an unapologetic speeder, as witnessed during a 1999 speech to the Legislature.

"Bill Janklow speeds when he drives -- shouldn't, but he does," Janklow said then. "When he gets the ticket he pays it, but if someone told me I was going to jail for two days for speeding, my driving habits would change."

In one notorious instance, two reporters were riding with Janklow when he made a 99-mph mad dash, through heavy smoke, down a mountain highway in the Black Hills to escape a raging forest fire in 2002. Janklow had tried to go faster, but the computer in his sport utility vehicle kept the engine from going past 99 mph.

Janklow received 12 speeding tickets from 1990 to October 1994. He was elected to a third term as governor a month later and never received another ticket in the state.

The jury was not allowed to hear about the tickets, but the prosecution was granted permission to present evidence of a close call at the same intersection where Scott died.

Janklow also said he has wished "a thousand times" that he would have eaten on Aug. 16. He told the prosecutor he does speed when he drives and he has run stop signs but that he would not speed through a blind intersection on purpose.

The Associated Press contributed to this report.