Killing of Qassem Soleimani “an act of war,” Margaret Brennan says

The latest escalation in tensions between the U.S. and Iran following the targeted killing of Qassem Soleimani comes after a series of skirmishes between the two countries in recent months. “Face The Nation” moderator Margaret Brennan joins “CBS This Morning” to discuss the ramifications of Soleimani's assassination.