I find that the game of Diplomacy is an imperfect analogue for real
relations among
nations. In the course of the
game (assuming you have players that care about their fortunes), there is always an abundance of spirited dialogue,
brokered deals, and
iron-clad pacts to break.
In the real world, it often seems that Diplomacy is the last item resorted to, as an afterthought. Frequently, unilateral action is taken. In some cases (such as dealings with terrorists, where they may be no central authority with which to negotiate), this may be necessary. And, in truth, the use of force and calculated silences are diplomatic tools.
But it is the ongoing process of relationship building that seems rare in the modern world. What real connection does America have to, say, the Islamic world? The fine people at Avalon Hill, in designing Diplomacy, have in fact given the world's nations something to think about.