Here's why John Bolton and John Kelly were at each other's throats today

CNN's "The Lead" Thursday reported that the intense shouting match between John Bolton and John Kelly, which escalated to the point where observers worried both men might resign, occurred over Secretary of Homeland Security Secretary Kirstjen Nielsen.

According to CNN reporter Kaitlan Collins, Bolton shouted that Nielsen needed to be better at her job, while Kelly defended the embattled Nielsen.