White House halts Pete Hegseth’s use of polygraph lie detector tests to catch media leakers—what are they and how do they work?

Defense Secretary Pete Hegseth’s hardline approach to uncovering media leaks inside the Pentagon just hit a wall, one built by the White House itself. According to The Washington Post, a senior aide close to Hegseth pushed back after being told he might be subjected to a polygraph test, the kind more commonly seen in crime thrillers than government offices.The tipping point came in April, when Patrick Weaver, a trusted advisor to Hegseth and longtime Trump loyalist, reportedly raised objections to the practice. Weaver, who is also aligned with White House Deputy Chief of Staff Stephen Miller, didn’t take kindly to the suggestion that he, or anyone in the inner circle, should be hooked up to a lie detector. His complaint reached the West Wing, triggering a call to Hegseth’s team to stop any such interventions.

This pushback comes amid Hegseth’s ongoing crusade to plug leaks from within the Pentagon, leaks that have frustrated senior leadership and drawn criticism from the Trump administration.

What is a polygraph test, and how do they work?

A polygraph, often called a lie detector, is essentially a bundle of sensors wired to track how your body behaves when you're under pressure. Think of it as a nervous system mirror: it doesn’t “know” if you’re lying, but it does pick up signals when your body might be reacting to deception.

The process usually involves strapping the individual to a series of monitoring devices. A pneumograph wraps around the chest to detect changes in breathing, while a cuff is placed on the arm to monitor blood pressure and pulse rate. Meanwhile, electrodes are applied to the skin to measure what's known as the galvanic skin response, how much a person is sweating, even in tiny amounts that might not be visible but indicate increased stress or anxiety.All of these physical responses are tracked in real time and recorded onto moving graph paper or digital charts. As the subject answers a series of questions, ranging from routine to potentially incriminating, the examiner watches for any physiological deviations.

A spike in heart rate, a sudden shift in breathing, or a noticeable change in sweat response may lead the examiner to suspect the subject is not telling the truth.

Are they accurate?

Despite the “lie detector” label, polygraphs don't uncover lies with any kind of scientific certainty. What they do track are physiological reactions, but those can be triggered by more than dishonesty. Feeling nervous, being afraid of being misjudged, or even just having a high level of anxiety can cause similar spikes in readings.Some supporters claim these tests are 80% to 90% accurate, especially when done by skilled professionals. Others—especially scientists and legal experts, say the numbers are wildly overstated. Results can shift depending on the person’s emotional control, intelligence, or even if they’ve trained themselves to stay calm under pressure.