Former NIAID director Anthony Fauci took an unexpected step during a closely watched Senate appearance on Wednesday, invoking the Fifth Amendment instead of answering questions before a committee led by Sen. Rand Paul. The move quickly changed the tone of what had been billed as a major Capitol Hill confrontation.

Fauci’s testimony had drawn attention because of his long-running public disagreements with Paul and his central role as a leading public-health official during the pandemic. Rather than a direct exchange between the two men, the hearing’s early focus shifted to Fauci’s decision to decline substantive testimony.

The moment stood out because the appearance had been widely anticipated as another high-profile chapter in the clash between Fauci and Paul. With the former health official choosing not to answer questions, the hearing became as much about the legal and political significance of that decision as about the issues the committee had planned to examine.

The development adds a new layer to ongoing scrutiny surrounding Fauci’s public service and his time at the National Institute of Allergy and Infectious Diseases. It also ensures that this latest Senate hearing will be remembered less for the expected back-and-forth and more for Fauci’s swift invocation of his constitutional right.