If I only hired people who agreed with my political views I'd have a hard time hiring anybody. It's important to realize and accept that two equally intelligent people can come to very different political viewpoints, and that these political viewpoints generally don't impact a person's ability to do their job.

That said, I strongly believe that political conversations don't belong in the office. I've been in both workplaces and graduate programs where one's political views were simply assumed. Sitting around in the middle of a one-sided political 'conversation' isn't fun - you have to decide whether you want to just politely keep quiet or speak up and potentially ruin your relationship with your co-workers. (While most people can handle differing political views, some hold grudges or assume you're stupid, and it's not easy to tell who's going to do this at first.) Neither option is particularly enjoyable when you just want to get your job done and get along with everybody.