With President Harry S. Truman's popularity at a low point, the Republican Party gained 55 seats with Robert Nodar Jr. defeating Delaney.

During the late 1950s, after a series of lurid magazine articles and Hollywood films helped to sensationalize youth gangs and violence, Delaney was one of the first congressmen to author legislation banning automatic-opening or switchblade knives in 1954.

On April 17, 1958, Delaney stated, "Every day our newspapers report numerous muggings and attacks, most of them involving knives.

[3] Rep. Delaney and other congressmen supporting the Switchblade Knife Act believed that by stopping the importation and interstate sales of automatic knives (effectively halting sales of new switchblades), the law would reduce youth gang violence by blocking access to what had become a symbolic weapon.

[5] Delaney later became chairman of a Select Committee to conduct an investigation and study of the use of chemicals, pesticides, and insecticides in and with respect to food products (81st and 82nd Congresses).

His political views tracked those of his constituents, which included many working class, but socially conservative Catholic voters.

[7] After his 1972 victory, Delaney moved closer to the Democratic fold and was eventually elected as the delegation leader in the House.

Delaney did not run for re-election in 1978, and future vice presidential candidate Geraldine Ferraro won the election to succeed him.