First, on a personal level, you should avoid any politically related discourse and encourage him to do the same in order to maintain a working relationship. Second, since he routinely broadcasts his opinions, you'll need to address this as well.

To prevent a toxic atmosphere from forming, call your co-worker aside and emphasize that making statements regarding his views will likely cause unintended tension and thereby affect the ability of your crew to work together successfully. While you must be adamant that he should refrain from political discussions in the office, assure him that he obviously has the perfect right in private or away from the workplace to think, feel, and talk about his political beliefs at full volume if he wishes. It is only in the office that he must exercise discretion.

Last, perhaps the best way to guarantee the peace is maintained in the office is to be sure you are modeling the behavior you want to see. As an old saying goes, "Nobody ever got in trouble keeping his mouth shut" – and it applies double when it comes to political matters. E