“I have 2 older daughters in their 30’s.”
The way you phrase this suggests you have other children besides them. If so, how are they different?
“Everything I say triggers them.” Is it possible you talk about politics too much? If so, cool it off for the summer. Events will continue to demonstrate a world spinning out of control and your daughters may start to be disturbed by them. Force them to focus on these by taking the focus off the arguments you always get into with them.
“Today I got in a fuss defending the gallantry of Southern soldiers.” It’s better to “show” than “tell” on a topic like this. Next time they visit, pop in North and South or The Blue and the Gray into the Dvd player.
“30 people a week shot in Chicago or New Orleans is OK but DeSantis is a racist.” At the end of the summer, when go back to talking about politics, bring up something Tim Scott or Vivek Ramawhateverhisname pointed out. Or RFK, Jr. Confound your daughters by talking about points and positions you agree with held by someone other than a white male Republican.
“I just want to communicate with my offspring. Why are my values always wrong?”
The trick is to find those values you have in common and somehow connect them to important issues and current events.
You say you are a retired history teacher. Watch some movies about key female historical figures and talk about them with your daughters. For instance, see Agora. https://en.wikipedia.org/wiki/Agora_(film)
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