Suppose while sitting around after Christmas gifts are exchanged, talking and catching up, someone says something about voting and the Republican uncle says,"You had to show ID to buy this beer, why shouldn’t you have to show ID to vote?" The Obamanista is programmed to say, "Only .00000013% of votes cast from 2002-2005 resulted in convictions or guilty pleas for voter fraud, so what problem are voter ID laws supposed to be fixing, exactly? All they do is make it harder for people of color*, women, younger voters, and seniors to vote. That’s un-American."
The site has prepared responses for numerous things a conservative relative might say. If you are going to be with your smart-ass Democrat nephew tomorrow you may want to know what he is going to be prepared to say in advance of him saying it. The site gives the liberal answer to anything that remotely touches on politics, everything from climate change, to Jeb Bush, gay rights, immigrants and refugees, Donald Trump, Marco Rubio, Ted Cruz, and more.
My suggestion is enjoy time with family but monitor your comments. Don't talk about anything important. Don't even talk about the weather. Don't have conversations. For one day stifle yourself. Don't give the little meathead an opening. You don't want Christmas to end with hurt feelings and people going home mad. If he baits you, don't take the bait. Just smile and nod a lot. Talk football or ask him how he likes his job, but don't relax. Don't let your guard down. Think about everything you say before you say it. If however, it is unavoidable and you cannot avoid saying something that gives him an opening, be prepared for it. If you go to this site, you will know what he is going to say before he says it and you can have your counter arguments prepared.
On the other hand you might just say, "Oh, I read that on 'Your Republican Uncle' and that is an interesting take on the topic, but maybe we better talk about something else. Excuse me, I need a refill."
*Note: If he says "people of color," in normal conversation, you all probably cannot really talk about anything anyway. Don't even try. Also if he can know that the conviction rate for voter fraud down to the eight decimal point he is a computer and not a real person.