China and Russia attacked a new report that outlines President Donald Trump’s national security strategy. Released on Dec. 18, the report says that Russia and China “challenge American power, influence, and interests, attempting to erode American security and prosperity.”

A spokesperson for Russian President Vladimir Putin said the report has an “imperial character” and accused the U.S. of seeking a “unipolar world.” China’s Foreign Ministry urged the U.S. to transition from what it called a “Cold War mentality.”

We’ll ask historian and security expert John Mearsheimer to analyze the reactions. He is professor of political science at the University of Chicago and author of numerous books on foreign policy and security including, The Tragedy of Great Power Politics and Why Leaders Lie: The Truth about Lying in International Politics.