Stars, Stripes and Enamel

Can you guess what these four men have in common?

Sure they've all had the honor of being President of the United States, but that isn't their most important shared attribute. Their most significant commonality isn't their role, status, ability, terms or representation, but instead one amazing thing...

The Flag Pin!

Here is to another term of ups, downs, frustrations, reliefs and filled and unfulfilled expectations. No matter what happens, remember to stay united and that we are all in fact on the same team, no matter how vastly different we may seem at times.

(Also I may have added the pin to Lincoln, but I'm sure he would have wanted to wear one)