@Individualist: Because your son is 6’4" and 258 lbs., I think that he’ll be okay. Otherwise, he will need to sharpen his diplomatic skills.
P.S. In answer to your question: “Should he attend CA ?” I think that it depends upon the thickness of his skin & how artfully he can express his opinions.
I will probably regret jumping into this discussion, but I’m going to take a shot in responding without getting into the merits of any particular position.
OP, I agree with I think is the consensus here, which is that I think it’s pretty unlikely that your child would be “bullied” (as I use the term) by virtue of political affiliation or by virtue of being a “conservative.” It has no place in boarding school, or any school for that matter, and I think it’s fair to say that it runs counter to the cultural norms of the boarding schools generally discussed in this forum. I would add that I personally don’t think that labels such as Republican / Democrat or Conservative / Liberal are really that insightful in a vacuum because, in my experience, people have myriad reasons for wearing one label or another and often have opinions on specific issues that many others would regard as stereotypical of the opposite label. I think most of the kids in these schools get that, and I think most of the kids understand what is expected of them in terms of cultural norms.
That said, I think these schools are full of energized kids, many of whom have strong opinions about political issues. And for anyone who is vocal about their viewpoints (whatever they are), they’re going to be judged (positively or negatively) by the audience for the viewpoint, as well as the strength of the logic and authority used to support the viewpoint. I think kids at these schools understand well the difference between someone who simply has a different viewpoint and someone who is being intransigent and arguing opinions as if they were fact. Also, when the views being espoused feel personal to the audience, it’s more likely it is to evoke an emotional response, just as it has in this forum. Will that affect interpersonal relationships and have some effect on friend selection? I have to believe that it will, but that falls well outside my definition of bullying. People can vocally support opposite political ideologies and be good friends–the example I like to use is Ginsburg and Scalia–if that they can maintain mutual respect for one another, but we remember the examples because they are notable.
Clear difference between having certain political views and broadcasting them to everyone he meets. I think he will be fine having those views, everyone is entitled to their own. The difference is how is he gonna be being with other students? Is his first conversation with someone about politics and will he immediately say why they’re wrong for x, y, or z views? If he’s relatively good socially then I’m sure he will find friends of all kinds of political viewpoints. Friends can certainly agree to disagree 
@PhotographerMom , you provided some great wisdom and maturity with your post.
MODERATOR’S NOTE:
Might I remind members of the forum rules: “Our forum is expected to be a friendly and welcoming place.”
Snark has no place on this thread. “I disagree with your opinion” is fine; “You’re crazy to think that” is not. Several posts deleted.
My daughter was at a HS where her liberal views were very much at odds with a very conservative student body. She had some run ins with fellow students that resorted to them name calling instead of constructive debate, but they were few and far between. Honestly, she graduated with a great ability to debate using facts, in a respectful, constructive way. It’s a life skill that is unfortunately lacking in our current environment.
I will say this, you will find that at essentially all the top NE prep schools a slight/moderate liberal lean by both the administration, faculty, and the students. Keep in mind, that these schools are located in MA, CT, etc. which is probably one of the most liberal parts of the country. I also am almost 100 percent sure that your child WILL receive backlash for his beliefs, but at the end of the day is it really important to keep him away from people who have opinions that are vastly different from his. Backlash is not the same as bullying. I doubt he will be bullied at CA, but he will be met with emotional opposition to almost all his ideas. If your son can accept that fact, CA is a great school that he will probably thrive in, but if his goal is to convince the school and students to agree with his viewpoints, he will be in for a very tough 4 years. On another note, while CA is liberal it is by far not the most liberal prep school. I would say that award either goes to Choate or Andover yet even those schools are moderately accepting of other viewpoints. On another note: I really like your son…while I don’t necessarily agree with all his points. I think it takes courage to want to go to a school where he will have the minority opinion and continue to hold his views.
I don’t know how people here can say your son won’t be bullied. I think that’s because there is a belief that people who are “leftist thinking” are higher than that but it isn’t the case. I know an adult in the northeast who used to speak out about his political views (he is right of center, well spoken, and reasonable) but has now stopped because he fears for his safety and the safety of his family. He has been bullied on social media and within his personal world.
So as to your son, I wouldn’t be so sure. I know many in the northeast who think center and/or right of center but keep their mouth shut because they don’t feel free or safe to speak up.
Well that’s because social media is the root of all evil ?
I know people who are big trump supporters. They aren’t bullied in the slightest. We have good conversations but it’s hard when two sides cannot agree on basic facts. When my daughter heard, one in particular that she is close with, was a trump supporter, she was shocked. It was a good learning experience for her.
Being bullied and having people roll their eyes at you are two different things.
Interesting to note how many on this thread have cited that he shouldn’t “force his opinions” on others or that others will be open to his opinion. Or that it will be good for him to learn to defend his position. Turn the tables and think about it. Would anyone want to learn in an environment that wasnt a two way exchange of ideas? I wouldn’t. Turn on TV and watch any news program, left or right were they supportive of the other view or did they mock them for having another opinion? There is little to no diversity of opinion in some schools. Kids can get worn down by having to defend their ideas all day long.
The idea that others will be respectful could easily be tested talk to other kids at revisit about his opinions and see their reactions.
We looked at CA and had two experiences that made it clear what the learning environment would be like. And we weren’t talking about politics or anything just talking to the teachers. Openess and balance two sides is important to our kids ( debaters). It was a huge factor in fit for our family.
Applicants should carefully consider fit in any decision. For us, there was a single school that felt like an echo chamber of ideas. No application was made. End of story.
Students and parents can feel out the vibe on revisits. Talk to parents what do they discuss? What does the head of school talk about? What matters to them is likely what will get passed down to your kid.
He is unlikely to find people who support or agree with his beliefs. He probably won’t be bullied, unless there are other aspects to his personality or behavior that put him at risk, but he will be challenged for his beliefs. If he’s looking for an atmosphere where there are others who support Trump, and don’t accept science, he should probably choose a different environment.
Could he shadow a student for a day so he can assess the vibe?
The OP did not stipulate either that the son required agreement or that the son rejected science, only that he not be bullied. Maybe I am imagining this, but I seem to detect a distinct note of concern among some of these responses. Think of the bratty younger brother - if your parents don’t let you just whack him, then you are completely at his mercy. I am reminded of the stand-up comic I saw on TV one time who said his rebuttal in HS debate was “well f*** you!”, and he thought that he had won! It’s one thing to say the other’s guy’s point is “demonstrably false” and another to actually “demonstrate” that it is false. With regard to climate change specifically, read some of Greenpeace co-founder Patrick Moore’s talks and you will see that this is no easy task.
Whatever your child’s “beliefs” (with air quotes), you should want them to go to a school that encourages a free exchange of ideas. Otherwise it’s just a “madrassa”, where the students memorize and recite “facts” from canon. Liberal parents, in particular, should encourage conservative parents to send their students to their schools, so that their own kids have some “sparring partners”.
It might be extremely hard to find a Science teacher at a top boarding school who agrees that climate change is a hoax. That doesn’t mean he’ll be bullied.
+1000 to @Happytimes2001 and @Empireapple. Great posts.
For me - the casual disregard for a teenager living away from home is striking. And the standard " elitist " justification for it is even more jarring. This thread should serve as a wake up call for everyone - especially ( and most regrettably ) the OP.
" Bullied, unless… " FWIW- here’s a tip : Those two words should never be used together in the same sentence. 
Your child won’t be bullied for having dissenting opinions. In fact, as long as they don’t infringe upon others’ rights, nobody will have any problem with that. He will certainly be in the minority, but he won’t be the only conservative student and nobody will bully him for that.
^ Thanks for this @CavsFan2003. The parents here are getting a little carried away. The kids themselves are the ones the OP should be asking.
Parents on this board actually have kids at some of the schools mentioned and some know kids at these schools so many on CC are speaking from experience based on their own kids, neighbors, colleagues kids and actual observations. I know more than 50 kids who attend various boarding schools. Possibly more and many alumni. Parents talk about their kids experiences. They also talk about other kids. We talk about who went where and how they are doing. So as a family we have a pretty good sense of things. We weighed things carefully as a family.
My 8th grader at the time was able to perceive many differences across the boarding schools including openess to various ideas, what was important at each school and more.
Parents on CC have also lived in a time when many opinions were acceptable in a classroom and others were not openly critiqued for having a different view. I personally miss living in a society where people debated and considered other opinions. I learned a lot from people who have different ideas. Still do. That’s why I support learning debate. But that said, as a parent I would carefully consider if any school my kids were attending wasn’t open enough to accept EVERY opinion. The spectrum is wide and opinion has merit. In our house, if you can’t understand and argue for someone else’s opinion, your arguments aren’t considered sound. That’s real debate. Being a good debater is being able to accept differences.
And you can’t infringe on someone else by having your own opinion. Opinions are just that, something You believe.
Putting aside any particular comment on this thread, it seems to me that, collectively, the various comments provide some insight into of the range of reactions your child might encounter. Although I don’t personally know any posters on this thread, I think it’s fair to say that the posters here are (on average) more educated and/or more informed about political issues than the general population. That higher level of education and knowledge clearly does not, however, translate to everyone having the same opinions, and it does not translate to people handling differences of strongly held opinions in the same manner. Even so, my sense is that nearly all (if not all) of the posters support the idea–at least in theory–that boarding schools should be a place where students can intelligently debate issues and discuss different perspectives, and no one wants a child to be bullied. I would not expect anything dramatically different from boarding school students.
I think people are reacting to the concept that in the absence of facts, debate is difficult. For example I can imagine my kid engaging in a conversation with OP’s kid about Trumps economic policy and weather the tariffs will be good or bad for the US. However, (and I’m picking a non-Trumpism on purpose here) is it reasonable to debate Kyrie Irving’s statement that the world is actually flat? @Happytimes2001 I wouldn’t be able to take the affirmative on that one. I think it’s that kind of position that people have in mind when they say the kid may get some push back (no idea if that’s what the OP had in mind when he wrote the post). If my kid was faced with someone trying to debate that with her I don’t think she would engage. I think she’d decide they were super foolish. She’s a kid after all and does NOT have the maturity of an adult.
As an adult I met someone who told me they didn’t believe in evolution, I was caught very off guard and laughed out loud. I guess I thought they were kidding or something. I had nothing to say, hard to debate that without being insulting.