President Trump moved quickly to remake American foreign policy in his first 100 days in office, weaponizing his “America First” agenda with the slashing of foreign aid, expansionist threats toward friendly countries,

He has disparaged NATO allies and embraced Russia's narrative about its invasion of Ukraine. And he has spoken about annexing Greenland, retaking the

Christiane Amanpour speaks with historians Jill Lepore and Timothy Garton Ash about President Trump’s first 100 days in office and America’s role on the world stage.