The briefing room at the White House in Washington on Sept. 19, 2026. The Justice Department is investigating whether the major television networks — ABC, CBS, CNN, NBC, and Fox News — violated federal antitrust laws when the group briefly suspended their pooled coverage of President Donald Trump, according to six people with knowledge of the department’s action. (Andrew Leyden/The New York Times) By DAVID McCABE, MICHAEL M. GRYNBAUM, BENJAMIN MULLIN, LAUREN HIRSCH and GLENN THRUSH The…