In 1832 Baker enlisted as a private to serve in the Black Hawk War. This was a war to protect the homes of the settlers from the savage Indians. It was fought in northwestern Illinois and southwestern Wisconsin. From this war Baker emerged a Major.
Colonel Baker moved to Springfield in the year 185 5. Living at Springfield at that time were Lincoln, Douglas, Trumbull and other men who in later years achieved national distinction.
His career began and ended in public service. He was elected representative of Sangamon County to the Illinois general assembly in 1837, served in the state senate from 1840 to 1844, and was nominated and elected representative to the National Congress as a Whig in 1844, defeating Abraham Lincoln for the nomination.
In Baker's willingness to serve his country, he resigned his office as congressman that he might raise a regiment in his state for service in the Mexican War. He was made Colonel of the Fourth Regiment of Illinois Volunteers. At the close of the war he moved to Galena, Illinois, and was nominated and elected to the Thirty-first Congress. He served his term, but declined re-election.
Baker went to the Isthmus of Panama in 1852, where he was to have a part in building a railroad across the isthmus. This road was made necessary by the heavy travel of gold seekers to California. Contracting a fever, he was compelled to return to the North. Instead of going to Illinois, he joined the gold rush to California, where he established himself in the practice of law. He soon had a reputation as an able lawyer and skilled debater. He was a candidate for Congress in 1859, but suffered defeat.
His defeat was partly brought about by his opposition to mob rule or the vigilance committee as a means of dispensing justice.
Shortly after his defeat for Congress, Baker removed to Oregon. In about eight months after coming to Oregon he was elected United States Senator. There were three political factions in the state at that time. One was led by Joseph Lane, the first Territorial Governor; another faction was led by J. W. Nesmith; and the third by Colonel Baker. The election of Nesmith for the long term and Baker for the short term was brought about by a fusion of the factions they led.
