If it's someone that you care about...

... then you wouldn't let that kind of stuff bother you. It's natural to want those close to you to share the same outlook as you. That can be a very reasonable expectation when it comes to wanting to share individual lifestyles, but on the political level that all breaks down. Humans did not evolve to have cogent political opinions about what an entire country should look like or how it should be run from half a continent away. Ultimately, one small vote doesn't mean much in the grand scheme of things, so to get hung up about how he or she votes isn't very rational. So when sharing political opinions the key is not to tell your loved one what they should believe, but rather to simply explain where you're coming from.