How did Eisenhower end McCarthy's investigation into his administration and the US Army?

Answer 1

President Eisenhower refused to openly confront or denounce Joseph McCarthy at any time. Instead he chose to make information available to discredit the man. He also persuaded the Republican Senators to censure McCarthy.

Answer 2

Eisenhower ended McCarthy's investigation into his administration and the US Army by allowing a televised Senate hearing where Army counsel Joseph Welch famously asked McCarthy, "Have you no sense of decency?" This marked a turning point in public opinion against McCarthy and contributed to his eventual downfall. Eisenhower did not directly intervene but allowed the process to play out and let public sentiment turn against McCarthy.