Adam Baldwin was personally responsible for the development of the Casey character, a character with which he identifies strongly. The photo of Reagan is his own personal photo, he often tweets Reagan quotes, and he is due to play Reagan in an upcoming film. In an interview with Big Hollywood, he talks about being openly conservative in Hollywood:
I do take the responsibility of portraying a guy who’s serious about
protecting the nation and I am a serious patriot, an American Patriot.
I believe that without our military, fighting men and women, that our
country would have fallen long ago. But they didn’t allow that to
happen so I support and defend that in my civilian capacity as much as
I can. And I try to portray that as well as I can. So, I love the
military. I love weapons as tools of defending liberty, individual
liberty, and freedom. I believe in the Constitution. I believe in the
American founding documents, or as Madison or Adams called them,
America’s political scriptures, which are the Declaration of
Independence, the Constitution and the Bill of Rights...
Casey defends, protects, serves America, which is what America’s
scriptures say, which is protect, secure life, liberty and the pursuit
of happiness. And, that’s what Casey, he is. You know, the folks (on
"Chuck") were accommodating to the fact that I brought a perspective
that they necessarily didn’t have in their life, or their creative
writing, that could make John Casey more authentic...
Did you keep the picture of Ronald Reagan that was in Casey’s apartment? Well, that was mine. That was a copy I have, so I have
the original. Yes.