Rather than honing one's de-escalation skills, instead affirm that political discussion is to be avoided, not because conflict is unpleasant and agreement is unlikely, but rather because family gatherings are more important than politics. Explicitly proclaim to your loved ones that the purpose of Thanksgiving is to reflect with gratitude on the preceding year in ways that enable otherwise dispersed family members to renew their familial relations. Like the current mileage on your car or the color of the interior of your local bank, the political condition of the nation is beside the point of Thanksgiving. Politics simply doesn't matter.
Their emphasis, but I agree entirely with the emphasized claim. People, for instance, who cut ties with family over party identification or voting practice are not so much participating in political life as corrupting it. It is like lopping off the feet because they won't fit the bed; it gets the order of means and ends completely wrong. No good can come of such behavior.