Debate Challenge? What to Call Your Opponent As Mitt Romney and President Obama huddle with their debate coaches this weekend, they will each have to make a simple - but potentially critical - decision ahead of Wednesday's face-off. What do they call each other? Will it be "Mr. President" or "the president" when Mr. Romney refers to his rival on the stage? Will Mr. Obama talk about the policies that "the governor" wants to pursue? Or will he talk about the impact of those policies from "my opponent"? Or will there be less formal moments, when "Mitt" and "Barack" slip out? Millions of people will be watching the two men in one of the very few direct interactions they have had during the 2012 campaign. Among the things being scrutinized: how much respect will each contender pay to his rival? "There's a certain amount of decorum that we expect in our debates," said Brett O'Donnell, one of the Republican party's top debate coaches. The reference that they use for each other is a beginning point for that decorum. Washington is famous for its fake friendliness - think of how often senators heap praise on their "good friend, the gentleman from Ohio" just before skewering the Ohio senator's motives and killing his legislation with a parliamentary maneuver. Presidential debates are no different. They are among the highest-stakes moments in American politics. Yet they demand smiles and handshakes at the beginning - a demonstration of respect and friendliness that is often at odds with the tough rhetoric that often follows. There have been few occasions in modern political history of outright nastiness or scorn when it comes to how presidential candidates refer to each other during debates. Still, campaigns have often made subtle choices as they seek an advantage. During the first debate between Mr. Obama and Senator John McCain of Arizona in 2008, Mr. Obama all but ignored Mr. McCain's decades as a senator, perhaps hoping not to draw too much of a contrast to his own short tenure in the chamber. Almost every time Mr. Obama referred to his rival during that debate, he simply used his first name. "I don't know where John is getting his figures," Mr. Obama said at one point. Another time, he said: "John, nobody is denying that $18 billion is important." Later, he spoke directly to Mr. McCain, saying: "John, 10 days ago, you said that the fundamentals of the economy are sound." In all, Mr. Obama used Mr. McCain's first name 25 times. By contrast, Mr. McCain referred to Mr. Obama as "Senator Obama" or "the senator" each time. "It was a backhanded compliment," Mr. O'Donnell said, recalling Mr. Obama's use of Mr. McCain's first name. On the outside, he was being friendly, trying to be comfortable. It was a way of being respectfully distrustful. Three weeks later, in the third debate of the 2008 campaign, Mr. Obama had apparently thought better of his choice. He called Mr. McCain "John" only once, referring to him as "Senator McCain" throughout the rest of the debate. That same year, Sarah Palin, the former governor of Alaska and Mr. McCain's vice-presidential nominee, asked her rival, Senator Joseph R. Biden Jr., "Hey, can I call you Joe?" while shaking his hand at the debate's opening. She went on to call him "senator" during most of the debate, but did drop the formality when responding to Mr. Biden's criticism of the previous Republican administration. "Say it ain't so, Joe," Ms. Palin said. There you go again pointing backwards again. Debate coaches often suggest that candidates do whatever they can to subtly undermine their rival's experience and stature. In 2004, President George W. Bush repeatedly referred to Senator John Kerry as merely "my opponent," even when referring to Mr. Kerry's Senate votes. Mr. Bush used the same approach four years earlier, when debating Vice President Al Gore. Sometimes he called him "the vice president," but often switched to "my opponent." Mr. Gore stayed with the formal "Governor Bush," reminding all who were watching of the limits of Mr. Bush's experience. Mr. Bush's father, George H.W. Bush, always referred to Michael Dukakis as "Governor Dukakis" in 1992. President Jimmy Carter was careful to say "Governor Reagan" during their 1980 debates. In fact, most presidential candidates seem to adopt that careful approach: be respectful by using a proper title that doesn't risk offending anyone. The exceptions seem to come in those unscripted moments when candidates either clash angrily or interact warmly, dropping for just a brief moment the formal pretense. Perhaps the most memorable of those moments came during a presidential primary debate in 2008. When a moderator asked Hillary Rodham Clinton why people thought Mr. Obama was more likable, she answered, "I don't think I'm that bad." Mr. Obama dropped his guard and stopped calling her "Senator Clinton" in a moment that helped breathe new life back into Ms. Clinton's campaign against him. "You're likable enough, Hillary," he said. No doubt about it.