The German U-boats blocked British Isle and attacked merchant ships affecting the trading business of US with British, but at some stage the U-boats started to attack ships taking the lives of unarmed passengers, as with the Lusitania ship, which 120 American died. The Germans were asked to stop the attacks but they did not and many US ships sank, shedding off US citizens lives. The submarine warfare enraged the US neutrality which then turned against the German and declared war on March 1 in 1917.
It strengthened Fidel Castro's position. The bay of pigs was a failed attempt to remove him from power. When it failed the U.S was exposed as trying to start a revolution with one of their "allies". This really hurt the U.S in the future because it led other countries not to trust them.
Ultimately, the end of the Vietnam war resulted in communist control of Cambodia,Laos,and Vietnam. The Vietnam war was fought between 1st of November in the year 1955 to 30th of April in the year 1975.
