 The source says Harris added, quote, we will not back down. We will follow our president's lead. In a separate White House all-staff call, Chief of Staff Jeff Zients told aides to keep their heads down and keep doing the work of executing on the administration's agenda. Tamara Keith, NPR News, Washington. The National Weather Service is warning of a potentially historic and deadly heat event in parts of the West Coast. NPR's Nathan Rott reports the triple-digit temperatures are forecast for millions of people through the Fourth of July weekend.