Former U.S. ambassador to Russia John Sullivan says Putin-Wagner truce is "evidence of weakness" of Putin

Former U.S. Ambassador to Russia John Sullivan and U.S. national security correspondent David Martin join "Face the Nation" to discuss the Wagner march toward Moscow, which Martin said the speed of which "came as a surprise" to U.S. intelligence, and the deal between Russian President Vladimir Putin and Wagner group chief Yevgeny Prigozhin.