South Dakota Close of Filing Sets Top Races As filing closed Tuesday the race between Sen. Tim Johnson (D) and Rep. John Thune (R) topped a competitive slate of contests inSouth Dakota, with nine candidates vying for the House seat Thune will leave behind. Thune's campaign should receive a major fundraising boost April 24 when President Bush comes to South Dakota to raise money for his Senate bid. Johnson will face a challenge to his renomination from farmer Herman Eilers, while Thune will be unopposed in the June 4 primary. In the House race, Gov. BillJanklow and former Sen....