President Vladimir Putin said on Thursday that Russia agreed in principle with U.S. proposals for a ceasefire in Ukraine, but crucial details need to be sorted out and any truce would have to deal with the root causes of the conflict. Putin said he may call President Donald Trump to discuss the issue, which the U.S. president said he’d be open to. Trump said he sees “good signals” coming out of Russia and offered guarded optimism about Putin’s statement. We spoke with Jennifer Kavanagh is a senior fellow & director of military analysis at Defense Priorities.