Former Rep. John Thune (search) will not seek the House seat being vacated by convicted Rep. Bill Janklow (search), the South Dakota Republican Party announced Tuesday.

"Although Thune will not be a candidate in the special election, a very strong field of Republican candidates is emerging," Randy Frederick, chairman of the South Dakota GOP said in a statement. "We are very confident that the State Central Committee will nominate a candidate who will prevail in the special election."

Thune, who fell 524 votes shy of defeating Democrat Tim Johnson in last year's Senate race, has been under pressure by state and national party leaders to seek office, either the House seat held by Janklow or the Senate seat that Minority Leader Tom Daschle (search) will be vying to keep next November.

Janklow was convicted recently of manslaughter after he killed a motorcyclist in a traffic accident over the summer. He is resigning on Jan. 20, the day of his sentencing. A special election will be held June 1 and Republicans had hoped a Thune race would scare off Stephanie Herseth (search), who ran a strong race against Janklow last year, from seeking the seat. Herseth, a 32-year-old lawyer, has not yet stated her plans.

Thune, a three-term U.S. congressman who won his last two terms with more than 70 percent of the vote, has considerable statewide popularity, and is believed to be a tough match to Daschle. Republicans control the Senate 51-48-1 with one independent who frequently votes with Democrats.

But Daschle is also primed for a fourth term, already sending out field organizers and collecting more than $3 million this year. Supporters say Daschle expects to collect $6 million more next year, leaving Thune with a difficult struggle to catch up.

But GOP supporters, including Sen. George Allen of Virginia, the chairman of the National Republican Senatorial Committee, could put together a strong donor base and help out the Republican whose state supported George Bush in 2000 and is likely to do so again in 2004.

Frederick said the state Republican Party is still accepting nominations to be put on the ballot for the June 1 special election to replace Janklow, and suggested that the party is anxious to hear whether Thune will decide to take on Daschle.

"The announcements and direct conversations, received by the party, indicate that an announcement for any other public offices will come at another date," he said.

The Associated Press contributed to this report.