JFK is a good example of this. He was constantly putting his larger plans and hopes at risk for hook ups.

The Logevall biography gets at a specific instance during WWII. JFK was having an affair with a journalist, I think she was Dutch, who had had significant contacts with major Nazis before the war. The FBI was monitoring her. She doesn't seem to actually have been a spy but there were serious concerns at the time. While this was all going on JFK had an important post in naval intelligence and would have been an excellent source.

He was transferred to the PT boats partially b/c he was high profile and some serious backers wanted to highlight the boat and his stature would raise the boats profile, partially b/c it was seen as a good recruitment tool for the Navy to have Joe Kennedy's son serving in the Pacific on these boats, and partially b/c the Navy was sketched out by JFK's inability to keep it in his pants.