U.S. President Donald Trump shifted his tone this week, casting doubt on the prospect of a summit between Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskyy. 

Trump’s frustration appears to be mounting, warning that “the next two weeks” could be pivotal. If there’s no progress towards a peace deal, Trump says he could weigh massive sanctions or massive tariffs or both. 

Joining the discussion: 

• Anton Fedyashin is a Russian and European affairs analyst and history professor at American University. 
• Dmitry Babich is a Russian journalist and political analyst.
• William Lawrence is a political science and international affairs professor at American University. 
• Peter Zalmayev is the director of the Eurasia Democracy Initiative.