Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
What's the U.S. plan on Russia's "all out" invasion? Plus, a look at the strategy for fighting ISIS.
(CNN) -Russia took Crimea, but the story doesn't end there.
Pro-Russian protesters are now battling for cities in eastern Ukraine, barricading themselves inside government buildings, and claiming independence in what the country's prime minister calls chaos "scripted" by the Kremlin to justify an even bigger land grab.
The White House now says some of these protesters are likely on Moscow's payroll.
Russia denies having anything to do with the pandemonium. But the White House is threatening new sanctions if President Vladimir Putin keeps pushing.
And all the while, tens of thousands of Russian troops remain on the border.
Former U.S. Under Secretary of State Nicholas Burns, now a professor at Harvard, joins CNN's "The Lead with Jake Tapper" to discuss.