They also both came from extremely wealthy families whose original sources of wealth were under a cloud.   

Trump's Grandfather in the Yukon and JFK's dad in booze closely associated with Prohibition.  

JFK's father was fired by Roosevelt as Ambassador because he didn't approve of the US participating in the war then going on between Germany and England.  

Trump's attitude toward European wars is such that Angela Merkel is saying today that the EU needs to rely on itself.