How does McCarthy try to smear Welch indirectly

Joseph Welch was a famous American lawyer who served as counsel to the US Army.

Welch was a famous opponent of Joseph McCarthy and is often lauded as being the person who finally turned the tide against McCarthy when he asked McCarthy if he had any decency left.

McCarthy tried to indirectly smear Welch by accusing one of Welch's law firm's lawyers as a communist.

Welch protected Fisher and attacked McCarthy for his inappropriate methods.