There isn't a great line regarding what is inappropriate to discuss with other people's children, but as I progress as a parent I am starting to believe that any political discussion with elementary-aged children who are not your kids or grand kids is unwise. Certainly, teachers should teach history, government, civics, etc. However, that should be the limit. The downsides of pushing your political worldview on someone else's kid are stronger than the positives.
Much of my opinion comes from the fact that adults don't usually have the requisite humility to discuss political issue appropriately even with other adults. Most political discussion involves first characterizing people who disagree with you as bad or stupid rather than having valid concerns. This is wrong, but it is typical. Speaking to kids like this only teaches them to approach things in a similar way.
Furthermore, I'm shocked that adults think that kids' parents might want someone else teaching them their political worldviews. Even in an environment where most people believe a certain way there are some who will not. It is more important rather than less important not to isolate those kids and make them feel like they don't belong.
I remember people talking politics to me and around me as a kid, and it did not occur to me at the time how inappropriate those conversations were. I've since had several moments as an adult where I realized, "Hey, that adult shouldn't have made the child me believe that conspiracy theory," or "Wow, now that I can articulate what was happening at the time I can't believe that adult slandered that politician to me that way."
For what it's worth, in my experience people with both right-leaning and left-leaning viewpoints felt the freedom to push their opinions. So, this is an adult thing rather than a right or left thing.
My kids are not as interested in politics as I was at their ages, however I do have an approach I take when a political topic is raised. I always emphasize that when we have a specific political belief that does not mean that people who disagree with us are bad or stupid. I am willing to tell them what I think of a specific issue if they want to discuss it, though.
For reference, most of the political questions I've fielded in the last few years have fallen in one of two buckets.
- "I've heard a lot of people say that President Trump is mean. Is that true?"
- "A lot of people don't like President Trump. Why is that?"
Sometimes I wish I was raising kids in a different era. I'd much rather be discussing political issues than politicians' tactics and dispositions.