General Atchison soon commanded a lucrative practice in his new home, where he continued to reside in the discharge of the duties of his profession until February, 1841, when his superior legal attainments, which were known and recognized throughout the State, won for him the appointment as judge of the district court of Platte county on its organization in February of that year, when he moved his residence to Platte City. It appears that in that day judges were appointed to this position by the Government, with the advice and consent of the Senate. The office was not made elective until several years after. In 1834 and 1838 he was elected to the Missouri legislature from Clay county. Upon the death of Dr. Lyon, United States senator, in 1838, Judge Atchison was appointed by Governor Reynolds to the vacancy in the Senate. It was by many considered that this appointment was merited and he had been recommended by Colonel Benton and other authorities of the Democratic party; by others it was said that the governor himself was ambitious of the senatorship and had selected Judge Atchison as a person who could be easily beaten at the next election. The death of Governor Reynolds, however, occurred before the meeting of the next legislature and Judge Atchison was elected with but slight opposition. He was reëlected for two more terms, the last of which expired March 4, 1855, during the administration of Franklin Pierce. Two years after this he moved his residence from Platte to Clinton county. He was elected president of the Senate to succeed Judge Mangun, a Whig senator from North Carolina. The 4th of March, 1849, occurring on Sunday, Zachary Taylor was not inaugurated until the following Monday. Judge Atchison thus, as presiding officer of the Senate, became virtually President of the United States during the term of twenty-four hours. In referring to this accidental dignity, on being interrogated as to how he enjoyed his exalted position, the venerable senator good humoredly replied that he could tell but little about it as, overcome with fatigue consequent to several days and nights of official labor, he slept through nearly his whole term of service.