represented Washington (1897–1899) in the United States House of Representatives, and was an unsuccessful candidate for election in 1898. In 1899, he served as a U.S. Commissioner for regulating customs laws between the United States and Canada, and was an unsuccessful candidate for the United States Senate. During the Spanish–American War, Lewis served on the staff of the adjutant general of the Washington National Guard as an assistant inspector general with the rank of lieutenant colonel. He was subsequently promoted to colonel, and served in a similar role in Cuba on the staff of John R. Brooke, followed by service on the staff of Frederick Dent Grant. In 1896, Lewis received 11 votes for the vice presidential nomination on the first ballot at the Democratic National Convention despite not yet having attained the constitutionally required minimum age of 35. In 1900, he was an unsuccessful candidate for the Democratic vice presidential nomination; he withdrew before the balloting, and the nomination was won by Adlai Stevenson. In 1903, Lewis relocated to Chicago, where he continued to practice law, and served as the city's corporation counsel from 1905 to 1907. In 1908, he was an unsuccessful candidate for Governor of Illinois. In 1913, Lewis was elected to the U.S. Senate from Illinois; he served one term (1913–1919), and was the Majority Whip for his entire term. In 1914, he was the Senate's representative at a London conference that considered way to ensure that laws and treaties guaranteeing safe sea travel could still be implemented as World War I was beginning. Lewis also served as chairman of the Committee on Expenditures in the Department of State from 1915 to 1919. A close ally of President Woodrow Wilson, Lewis was a leader in getting much of Wilson's "New Freedom" legislation passed. Lewis also performed unspecified special wartime duties in Europe which led to him receiving knighthoods from the kings of Belgium and Greece. In October 1918, Lewis was aboard an army ship, USS Mount Vernon, when it was hit by German fire. Lewis and others survived the blast, but 35 of the ship's crewmen perished. Upon his defeat for reelection in 1918, Lewis was offered the ambassadorship to Belgium, but he declined and returned private legal practice in Chicago, Illinois. In 1920, he ran unsuccessfully for governor. He eventually became a partner in the newly named Lewis, Adler, Lederer & Kahn (now known as