Complex sentence: He served as a member of the New Hampshire House of Representatives from 1846 to 1850 and ran unsuccessfully for Governor of New Hampshire in 1854 and 1855 but was elected to the United States Senate for the term beginning in 1855.
Split into simpler sentences: He served as a member of the New Hampshire House of Representatives from 1846 to 1850. He ran unsuccessfully for Governor of New Hampshire in 1854 and 1855 but was elected to the United States Senate for the term beginning in 1855.