Schwengel had founded the United States Capitol Historical Society in 1962, and continued to serve as its president after his defeat, until 1993.

He also served as the President of the Iowa Chamber of Commerce and chairman of the National Civil War Centennial Commission and the Joint Sessions of Congress for the Lincoln Sesquicentennial.

Schwengel ran and won the Republican nomination for the seat,[6] and easily defeated John J. O'Connor in the general election.

Redistricting before the 1972 election shifted several Republican areas out of the 1st district, so when Mezvinsky ran against Schwengel a second time in 1972, he won with 53 percent of the vote.

While conservative on fiscal issues, he was very pro-labor and pro-civil rights, and was a strong supporter of separation of church and state.

Schwengel received the first JM Dawson Award from the Baptist Joint Committee for Religious Liberty in 1986[15] for, among other things, his stance against school prayer in 1970 that eventually led to his defeat from Congress.

At the onset, Schwengel was strongly supportive of this merger, and influential in the decision as a much-loved past president and ritual author for Phi Sigma Epsilon.