Which analyzes why some historians believe that the federal civil defense administration (fcda) used propaganda to reduce the general public’s concerns about nuclear warfare? historians believe that the fcda used civil defense measures as a psychological tool to convince civilians that preventive measures could be taken. historians believe that the fcda generated reports that underestimated the missile gap to put americans’ minds at ease regarding a nuclear attack. historians believe that the fcda’s warning system established a false sense of security to eliminate citizens’ concerns about a nuclear attack. historians believe that the fcda exaggerated false claims that the government had taken measures to eliminate the threat of nuclear attack.