Tuesday was the first time Waltz faced lawmakers since mistakenly adding a journalist to a private Signal chat used to discuss sensitive military plans.
Republicans inserted language restricting military actions on U.S. soil and blocking unsecure communications among senior officials in their 2026 budget.
The inspector general’s investigation focuses on how information about the March 15 airstrikes on Houthi targets in Yemen was shared on the messaging app.
A survey of more than 1,400 Iraq and Afghanistan veterans found concerns across party lines about the White House's handling of national security issues.
Hegseth reportedly had an internet connection that bypassed Pentagon security protocols set up in his office to use the Signal app on a personal computer.