In the excerpt from the "four freedoms" speech, why does roosevelt see the present threat to american security and safety as unprecedented?

Because at no previous time had American security been as seriously threatened from without as it is today. Since the permanent formation of the government under the Constitution in 1789, most of the periods of crisis in our history have related to domestic affairs. Fortunately, only one of these — the four-year war between the States — ever threatened national unity.

.elections are held to determine who serves in congress.

the hyksos invasion. the hyksos were able to attack egypt successfully because of their skills in using bronze weapons, composite bows and the use of the horse and chariot during the invasion. although the egyptians depict a barbarian-type overthrow, the truth is the seizure was likely a relatively peaceful one.