What’s up with Republican-turned-unaffiliated-turned-Republican-turned-Democrat voter Mike Derrick?

What’s the story with Republican-turned-unaffiliated-turned-Republican-turned-Democrat voter Mike Derrick?  According to the Glens Falls Post-Star, Derrick recently moved back to New York State from Colorado and is “looking very carefully at the possibility of running in the 21st District” against Elise Stefanik.  Down with Tyranny, a liberal Democratic website, highlights Derrick’s ever-changing party affiliation (in a larger not-so-flattering story about his Democratic credentials).

This raises a fair question – what exactly do the voters know about Mike Derrick?  What caused him to register as a Republican in 1980 only to register as an unaffiliated voter in 2006 before registering back as a Republican in 2012 only to register as a Democrat in 2015?

Have Mike Derrick’s positions evolved to the left, or does he just see some sort of political opportunity?