Did NATO's previous rounds of expansion, and the tensions they generated with Moscow, foment Russian President Vladimir Putin's war on Ukraine?
As the alliance considers expanding again by adding Sweden and Finland, Fareed retraces post-Cold War history with Member of European Parliament and former Polish Foreign and National Defense Minister Radosław Sikorski and Charles Kupchan of the Council on Foreign Relations, who served as senior director for European affairs in President Barack Obama's National Security Council.