Abraham Lincoln and Millard Fillmore had the same title. They were both presidents of the United States, but their tenure in office and their legacy could not be more different.
Both President Kennedy and President Reagan were roundly criticized by parts of the foreign policy establishment that felt they were being weak by engaging our adversaries. So some of it is built into a political lexicon that makes you sound tougher if you don't talk to somebody, and rather, very loudly, wield a big stick.
I do solemnly swear that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States
The President does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation.