Congress created Iowa Territory in 1838, from what was formerly the Iowa District of Wisconsin Territory. As a result of the Act of March 3, 1839, the position of Iowa Territory's Delegate to the U.S. House would become vacant on October 27, 1840, and Dodge was elected to fill it. After initially serving in the Twenty-sixth United States Congress, he was re-elected in 1840, 1842, and 1844. He served as delegate until Iowa became a state in December 1846, and his role was replaced by two voting Representatives.
Senator
For its first two years, the Iowa General Assembly failed to choose Iowa's first U.S. Senators, due to a three-way split that prevented any candidate from earning the required number of 30 legislators' votes. However, after the 1848 elections gave the Democratic Party a greater share of Iowa legislators, Dodge were elected as Iowa's first two U.S. Senators. By drawing lots, Dodge received the seat with the shorter term, but was re-elected that year to a full six-year term. While in the Senate, he served as chairman of the Committee to Audit and Control the Contingent Expenses, the Committee on Pensions, the Committee on Revolutionary Claims, and the Committee on Public Lands. In 1854, as Dodge's second term was near its end, the Iowa General Assembly chose Free Soil Party member James Harlan, rather than Dodge. Dodge was the preferred choice of Democratic legislators, whose ranks had declined. But in a failed effort to defeat Harlan by uniting Democrats and nationalist Whigs behind a single candidate, Dodge dropped out after the fourth ballot. Dodge served in the Senate until February 22, 1855, when President Franklin Pierce appointed him to the post of minister to Spain. He served as the minister until 1859.
Life after the Senate
Dodge unsuccessfully ran for Governor of Iowa in 1859, losing to Republican Samuel J. Kirkwood. He served as mayor of Burlington, Iowa from 1874 to 1875. In 1868, Dodge supported the candidacy of George H. Pendleton for the Democratic presidential nomination. Looking toward the 1872 presidential election, Dodge recommended Thomas A. Hendricks as a "worthy, able and excellent man." He believed that there was strong support throughout the Midwest for the Indianan, although he doubted that Hendricks would run well in the East. He died in Burlington on November 20, 1883, and was interred in Aspen Grove Cemetery. His father, Henry Dodge, served as a U.S. Senator from Wisconsin. They are the first, and so far only father-son pair to serve concurrently in the U.S. Senate. He was also the nephew of Lewis F. Linn. His brother-in-law James Clarke served as the third and last Governor of Iowa Territory.
