Following his time as governor, Temple was elected to the
Delaware Senate and served in three sessions, from the 1849–1850 session through the 1853–1854 session. With the demise of the
Whig Party, he was too conservative to support the agenda of
Stephen A. Douglas, but too fearful of disunion to support the
Republican Party or the eventual candidacy of
John C. Breckinridge. In the
election of 1860, Temple sought the elusive middle ground, and was one of the Delaware leaders of the short lived
Constitutional Union Party. This party supported the right of each state to decide the slavery question, but argued that somehow that right could be preserved within the Union. After the election of
Abraham Lincoln and the
secession of the Confederate states, Temple took a position opposing the enforced restoration of the Union, and joined the
Democratic Party. After presiding over a futile "
Peace Convention" in Dover in June 1861, he became the
Democratic candidate for the
U.S. House of Representatives in the hotly contested and controversial 1862 election. Temple's opponent was the incumbent
Republican George P. Fisher, who had served as
Secretary of State when Temple was governor. Now, Fisher was convinced that there were various schemes being planned to prevent a legitimate election. Accordingly, he requested that
Abraham Lincoln leave the Delaware troops in the
U.S. Army home until after the election, and that he send additional Federal troops to supervise the polls on election day. The Democrats were outraged and managed to narrowly elect Temple and a majority in the General Assembly, although losing the governorship. While officially a member of the
U.S. House from March 4, 1863, Temple died before the December convening of the House, and consequently never actually served. He was forty-nine years old. In a subsequent special election,
Republican Nathaniel B. Smithers won the seat due to a
Democratic Party boycott of the election in protest of the continuing presence of Federal troops at the polling places. ==Death and legacy==