The contest for President Obama's former Senate seat was a decidedly negative affair. Mark Kirk, a congressman, had to defend himself against charges that he misstated aspects of his résumé; Alexi Giannoulias was dogged by the failure of his family's bank.A Republican will soon hold the Senate seat once held by President Obama, with Mark Kirk earning a hard-fought victory in a result that perhaps best symbolizes the rejection of one-party rule in Washington.