In 2000, McDonald ran for the Nebraska Legislature from the 41st district,[3] following incumbent Senator Jerry Schmitt's decision not to seek re-election.[4] In the primary election, he faced physician Richard Hanisch, farmer Errol Wells, and financial analyst Don Smith.[5] McDonald placed second in the primary, receiving 36 percent of the vote to Wells's 38 percent,[6] and they advanced to the general election.[7]
During the general election campaign, McDonald suffered weight loss and severe fatigue, and was ultimately diagnosed with kidney cancer. He underwent a nephrectomy at the Mayo Clinic and resumed his campaign.[8] McDonald narrowly defeated Wells, winning 50.3 percent of the vote to Wells's 49.7 percent.[6]
Prior to the beginning McDonald's legislative service, doctors discovered a tumor on his spleen,[9] He underwent surgery to remove his spleen after the session started, and returned to the session shortly thereafter.[10] In March, he planned to undergo a third surgery,[11] but instead received a four-week long neutron therapy treatment in Batavia, Illinois, and participated in the legislative session over the internet.[12] McDonald returned to the session in May.[13]
On August 5, 2001, McDonald died.[14] His widow, Vickie McDonald, was appointed by Governor Mike Johanns as his successor in the legislature.[15]