By Brian Lowry

Say what you will about Bill O’Reilly, but his brand of conservative populism provided the foundation upon which Fox News was built, and in many ways anticipated and helped shape the views and resentments that lifted Donald Trump into the White House.

Given that, O’Reilly might be one of the best weathervanes to understand which way the winds are blowing in the MAGA movement, amid feuds among media figures — many of whom directly or near-directly inherited O’Reilly’s mantle — split on issues like Iran, Ukraine, immigration policy, and most recently, those Jeffrey Epstein files, or lack thereof.