But the next question I ask is: Why? Why do you care? Is it because you know the people involved? Of course not.
I don't root for U.S. swimmer Ryan Lochte over France's Yannick Agnel because I know them both personally and I happen to like Lochte more, or because my personal knowledge of the two tells me that Lochte is more deserving in some larger sense (i.e., he works harder, has overcome more obstacles, etc.). I have no idea, yet for some silly reason, I get a certain pleasure when some American I've never even met does well.
This tendency is even more true of team events: I really have no way of knowing if the American team is nicer, smarter, more ethical, etc., than any of its foreign rivals. Yet I find myself cheering for a bunch of strangers who, for all I know, might be mostly jerks.
But even though I know all this, most of the time I can't quite stop myself from being inwardly pleased when the Stars and Stripes are up on the podium, and I can't help feeling a bit disappointed when some American individual or team flames out.
Some of this may be because coverage here in the United States tends to focus on the American athletes (and in a pretty flattering way), but that is both a reflection of nationalism (NBC knows American viewers want to watch their countrymen) and one of the things that reinforces it.
This feature of nationalism is what author Benedict Anderson famously meant by the phrase "imagined community." A nation is a group of people that imagines itself to be part of a common family, even though most of the members do not know each other personally (and might not like each other if they did). Yet they have the sense of being tied together, to the extent that when one member of the group succeeds or fails, it actually affects other members who don't even know him or her.
This tendency isn't absolute, of course (i.e., there may be some U.S. athletes I don't care much for, just as there are some members of the Boston Red Sox I've never warmed to very much). And in those cases, I won't be sorry if they don't emerge triumphant. But the general rule applies because nationalism remains an incredibly powerful political force. Try it on yourself the next time you turn on the Games.
Stephen M. Walt is a professor of international relations at Harvard University. He wrote this for Foreign Policy.