Final answer:
The false accusations made by Senator Joseph McCarthy against the U.S. Army during the televised Army-McCarthy Hearings in 1954 led to widespread public disapproval and ultimately a Senate censure, ending his career.
Step-by-step explanation:
The false accusations against the U.S. Army led to the downfall of Senator Joseph McCarthy. His persistent allegations, without ever producing evidence, contributed to what is known as McCarthyism. This peaked with the Army-McCarthy Hearings in 1954, which were televised nationally. During these hearings, McCarthy's aggressive and unfounded accusations were exposed, and his conduct was met with disdain from the public and his political peers. This resulted in the U.S. Senate censuring McCarthy for improper conduct, marking the end of his career and influence.
Illustrative of McCarthy's tactics was the incident with Joseph Welch, the Army's chief counsel, where Welch's famous rebuke "Have you no sense of decency, sir, at long last?" encapsulated the nation's growing weariness of McCarthy's belligerent and baseless accusations. Following these events, McCarthy lost his public support and was formally condemned by the Senate, effectively concluding his political influence and precipitating his demise.