The Modern Translation
Lincoln was not asking anyone to agree. He had just spent thousands of words disagreeing, and then he closed by reminding his audience who they were to each other. That is the move for your uncle and the gravy boat. Passion is allowed. Your pulse may rise, and your cousin may stop chewing mid-roll. The line only asks that the strain stay a strain. Before you answer, say one true thing about the person instead of the topic: "I know you care about this, and I like that you do." Then say your piece once, briefly, and offer pie. Notice what this does to the room. Your mother exhales, the uncle stops performing for the table, and the argument shrinks to the size of one disagreement instead of a verdict on the whole family. You do not have to win before the pumpkin pie comes out. You only have to still be related when it does, and ideally still be invited to the next dinner too.
The Text-Message Version
Try It Today
At your next family meal, or on the phone today, pick one person you tend to argue with. Before saying anything about the topic, say one warm, true sentence to them, such as "I'm glad you're here." Then state your view once, calmly, and stop. Afterward, notice how your shoulders feel and whether the conversation stayed smaller than you expected.