All through out the Cuban Missile Crisis, the U.S. was in def con 5. Which is 1 step away from Nuclear warfare. If JFK was less cool about everything, the world would have gone into nuclear warfare. I suggest watching this vid it gives you more of an idea of what it was like :)
Checks and balances is a system were the goverment checks the other two braches of goverment, and balance them out. so if the execuative branch gets to much power, the judicial and legislative branches bump down the power of it.
