Invoking the Fifth Amendment (and Other Protections) During Congressional Testimony

On July 9, 2025, former President Joe Biden’s physician, Kevin O’Connor, refused to testify before the U.S. House of Representatives in response to the House’s efforts to assess the former President’s mental acuity while in office. In doing so, Dr. O’Connor cited both his Fifth Amendment privilege against self-incrimination and the doctor-patient privilege. His refusal has garnered significant attention in the media, and it has raised questions about when the Fifth Amendment protection applies, why Dr. O’Connor may have been concerned about testifying, and what this means for the House’s efforts to obtain his testimony going forward.

The Fifth Amendment: Due Process and the Privilege Against Self-Incrimination

The Fifth Amendment includes several key protections for U.S citizens and foreign citizens alike. Along with protecting criminal defendants’ right to due process and prohibiting double jeopardy, the Fifth Amendment is also the source of the privilege against self-incrimination (also commonly referred to as the right to remain silent). Despite the fundamental role that this privilege plays in federal investigations and grand jury proceedings (and in state court proceedings under the Fourteenth Amendment’s due process and equal protection clauses), it is extraordinarily simple in its text. In pertinent part, the Fifth Amendment simply states:

“No person shall be . . . compelled in any criminal case to be a witness against himself . . . .”

That’s it. That’s the entire Fifth Amendment protection against self-incrimination.

This raises several important questions—and the Supreme Court has answered many of these questions over the past 200-plus years. Other federal courts have addressed these questions on numerous occasions as well. Regarding Congressional testimony, there is one obvious question in particular: Since the Fifth Amendment protection against self-incrimination applies to “any criminal case,” does it apply to Congressional hearings at all?

Today, the answer to this question is a clear, “Yes.” As the Congressional Research Service (CRS) explained when discussing former National Security Advisor Michael Flynn’s refusal to testify before the Senate Select Committee on Intelligence in 2017:

“As a general matter, witnesses may invoke the Fifth Amendment privilege during a congressional investigation with  regard to testimony or documents that are: (1) testimonial (“relate[s] a factual assertion”); (2) self-incriminating (any disclosures that tends to show guilt or that furnishes any “link in the chain of evidence” needed to prosecute); and (3) compelled (not voluntarily given). Oral testimony given pursuant to a subpoena and in response to committee questioning almost always qualifies as testimonial and compelled . . . .”

As the CRS went on to explain, this means that, in most cases, the key question is whether the testimony sought by Congress would be “incriminating.” The Supreme Court has held that the answer to this question is largely in the eye of the beholder. As the Supreme Court ruled in the case of Kastigar v. United States (1972):

“[The right against self-incrimination] can be asserted in any proceeding, civil or criminal, administrative or judicial, investigatory or adjudicatory; and it protects against any disclosures that the witness reasonably believes could be used in a criminal prosecution or could lead to other evidence that might be so used.”

As this makes clear, if the witness believes that statements made in response to questioning could be incriminating, then assertion of the Fifth Amendment right against self-incrimination is justified. The Supreme Court has also clarified that the Fifth Amendment privilege applies even when it is not clear whether a witness is at risk of facing criminal prosecution under federal law. As the Supreme Court stated in Ohio v. Reiner (2001):

“[W]e have emphasized that one of the Fifth Amendment’s “basic functions . . . is to protect innocent men . . . `who otherwise might be ensnared by ambiguous circumstances.'” . . . [and] that truthful responses of an innocent witness, as well as those of a wrongdoer, may provide the government with incriminating evidence from the speaker’s own mouth.”

Due to its breadth, the Fifth Amendment right against self-incrimination is frequently asserted in all types of administrative and judicial proceedings—from federal criminal investigations and grand jury proceedings and state court criminal proceedings to Congressional hearings. If an individual who is called to testify has a reasonable fear that his or her statements may be incriminating in any related or unrelated proceeding, that individual has the right to remain silent.

The Doctor-Patient Privilege: Protecting Confidential (But Non-Incriminating) Information

Since witnesses generally have the right to assert the Fifth Amendment privilege in response to Congressional inquiries, some people have questioned why Dr. O’Connor would also assert the doctor-patient privilege in order to avoid speaking with government officials. The simple answer is that the Fifth Amendment privilege and the doctor-patient privilege provide different—but, in many respects, equally important—protections.

The doctor-patient privilege protects communications between healthcare providers and those in their care regardless of any criminal implications. This privilege exists to ensure that patients can speak freely with their doctors without fear that their personal information will be disclosed.

It is worth noting that HIPAA, ethics rules, and various other sources of authority also prohibit doctors from sharing information about their patients in many cases. As a result, there are several considerations at play; and, as a general matter, doctors need to be extremely cautious about providing any patient-related information to any third party.

Asserting the Fifth Amendment: Congress and Its Investigative Authority

Congressional committees have broad authority to conduct investigations into an extraordinarily wide range of matters, and Congress’s subpoena power affords the ability to take the testimony of both accused persons and witnesses. Both accused persons and witnesses may have a variety of reasons why they would choose to assert the Fifth Amendment privilege (among other privileges)—not just in response to specific questions, but in order to avoid testifying at all.

Dr. O’Connor has asserted his privileges and obligations in order to avoid appearing before the House committee during its investigation into former President Joe Biden’s mental acuity. While some Representatives have implied that Dr. O’Connor is seeking to avoid admitting that he has lied in the past, asserting the Fifth Amendment privilege (among others) is not itself evidence of a violation of federal law. As discussed above, there are a variety of reasons why someone—and a person in Dr. O’Connor’s position in particular—may choose not to testify, and this makes it impossible to infer any particular state of mind or potential criminal culpability from a refusal to testify alone.

There are also a variety of reasons why someone may choose not to testify at all as opposed to asserting the Fifth Amendment right against self-incrimination in response to specific questions. Among them, in a broad inquiry like a Congressional investigation, it may not be clear what risks are involved. In high-profile investigations in particular, Congress often works with government officials from the U.S. Department of Justice (DOJ), Federal Bureau of Investigation (FBI), and a variety of other federal agencies—and providing any testimony at all can open up a can of worms that can be extraordinarily difficult (and costly) to close.

Furthermore, even with a defense attorney present, deciding whether to assert the Fifth Amendment right against self-incrimination in response to potentially high-risk questions on a case-by-case basis can be challenging at best. Refusing to answer specific pointed questions can also provide insight into a witness’s or target’s legal concerns—even if the refusal itself does not legally imply criminal culpability. This, combined with concerns about doctors’ ethical and legal obligations, makes it unsurprising that Dr. O’Connor has chosen to remain silent in response to the U.S. House of Representatives’ investigation.

In this particular case, it is noteworthy that the DOJ is already conducting a parallel investigation as well. As reported by Politico, in asserting Dr. O’Connor’s privileges on his behalf, his attorneys stated that in addition to the concerns raised by Congress’s inquiry, “the ongoing Justice Department investigation into the same subject raised the risk of potential incrimination – even though they insisted it did not imply the doctor had broken the law.” This is consistent with the broad principles underlying the Fifth Amendment’s protections, as discussed above.

In short, in light of the various protections (and legal requirements) that apply—and in light of the politicized nature of the House’s inquiry—it is not surprising that Dr. O’Connor has broadly asserted the Fifth Amendment privilege and the doctor-patient privilege in refusing to testify. Even if he has not been formally accused of a crime, and regardless of whether he is concerned about being charged with a crime, there are valid reasons for electing not to testify in this scenario even setting aside the politics involved.

Contact Oberheiden P.C. for More Information

Oberheiden P.C. is a federal compliance and defense law firm that represents high-profile clients in matters involving Congress, the federal courts, the DOJ, and other federal investigative and law enforcement authorities. The firm is led by founding attorney Dr. Nick Oberheiden, and its team includes several former high-ranking federal government officials and DOJ attorneys. If you would like more information, please call 888-680-1745 or contact us online to schedule a call with one of our senior attorneys today.