If a security threat is deemed drastic enough to declare war. true or false

It is true that Security threat is drastic enough to declare war.

Security is what matters on top with some war-related causes. When Security is controlled War can easily be arranged. In the US constitution, Congress has given the authority to declare the war. This is why presidents, so as FDR after Pearl harbor, ask Congress as their authority to go to battle.

If Congress decides not to declare war, only the president can do is send troops into a precise land/region for 90 days. If later then 90 days Congress has not declared war, then the troops must turn homeward.