U.S. sending more military aid to Ukraine as major new battle with Russia looms

The U.S. is sending another $800 million worth of military aid to Ukraine. CBS News national security correspondent David Martin got an exclusive look at a shipment heading to Eastern Europe, and retired Army Colonel David Johnson, a principal researcher at the Rand Corporation, spoke with CBS News' Nancy Chen and Vladimir Duthiers about the Biden administration's military support for Ukraine and reports of Russian forces possibly using chemical weapons.