Thirty years ago this month, Britain and Argentina were at war over a group of islands in the South Atlantic - we call them the Falklands and they call them the Malvinas. British forces recaptured the islands after an Argentinian invasion, but the diplomatic issue over who they should belong to has never gone away.
This week it resurfaced at the meeting of G20 leaders in Mexico. It was a silly and very public outbreak of name-calling in a corridor. The other world leaders looked on in astonishment given the importance of the real G20 agenda - saving the world economy, no less. But the Falklands, or Malvinas, still count for a lot in the domestic politics of both countries. The British Prime Minister David Cameron and the Argentinian President Christina Kirchner were both blatantly playing to the gallery back home. The British were attacked for being colonialists and accused Argentina in turn of refusing to accept the democratic will of the islanders.
It matters only because it's a reminder of something world leaders and diplomats forget at their peril. International groupings like the G20 or the United Nations or the European Union are both valuable and necessary. But it's still the national state that matters to most citizens. And for many of the public, who struggle to understand bank bail-outs and currency support mechanisms, the simple question of whether this or that patch of earth should be ours or theirs makes sense - and seems important.
As it happens, I've been to the Falkland Islands. While I'm instinctively opposed to hanging on to former colonial outposts, there's no doubt that they look and feel British right down to the last sheep and blade of grass. They're clearly not going to change hands any time soon. Argentina knows that, although that doesn't stop them having every right to argue that they should. Imagine how you would feel if Boston was still British. Then the Tea Party really would have something to shout about.
I like to think of myself as a true internationalist. I don't go in for all that flag waving stuff. But I know that you can't build support for the UN or the EU by riding rough-shod over national pride. Those other world leaders would have been wrong to dismiss this week's spat as irrelevant because it actually went to the heart of what makes international diplomacy so difficult and so important.
This is Lance Price for CBS News in London.