History reveals several pathways to war; but, as the tension between the West and Iran revs up, two seem particularly relevant because of the lessons they offer for those seeking to contain the crisis.
The first might be called "slip-sliding into conflagration," and World War I (not that any dust-up between Iran and its adversaries will metamorphose into a global conflict) is an exemplar.
In August 1914, none of the parties -- no, not even the Kaiser Wilhelm II -- set out to ignite a major war, let alone one that would last four years, kill millions, ravage Europe, destroy four empires, and lay the groundwork for another worldwide conflagration. Indeed, even as Wilhelm waved his troops off to battle, he assured them that they'd be back "before the leaves fall from the trees" -- i.e., the end of that autumn.
In the run-up to the "Great War," the belligerents made a series of incremental moves, which, in combination, created a disaster of epic proportions.
As it dawned them that a horrendous war might be in the offing, the Russian and German monarchs (Wilhelm and his cousin Tsar Nicholas II) made a last-ditch effort (in a series of frantic missives since known as the "Willy-Nicky telegrams") to stop the juggernaut; but to no avail. By then, to paraphrase Ralph Waldo Emerson, events were in the saddle and riding mankind.
Let's call the second pathway "war by premeditation." Adolf Hitler best personifies this example. He deliberately used war to overturn Europe's balance of power and territorial demarcations. For him, war as a glorious, purifying enterprise, and the price was worth it. No slip-sliding for Adolf. And no unintentionality either: he didn't stumble into the invasion of Russia in 1941, his biggest blunder -- he had long planned it.
Apocalyptic scenarios are common these days in discussions of Iran. One involves an Iranian nuclear "breakout" (in plain English, Tehran detonates a bomb). Another centers on or an out-of-the-blue preventive attack by Israel, which then creates irresistible pressure on the United States to follow suit, especially in an election year when who's really tough is among the questions candidates are telling voters to ask themselves about their rivals. But there's little chance that any of the parties to the crisis will take the World War II route to war.
Iran's leaders are not dumb. They know that as long as they don't cross the nuclear Rubicon, they can avoid isolation and ensure that China and Russia block any Security Council resolution that tightens existing sanctions and lends international legitimacy to the added pressure. More importantly, Tehran understands full well that clear signs of an impending breakout will provoke an American, or more likely Israeli, attack.
Western leaders routinely underscore Iran's increasing isolation. But a number of important states (aside from Russia and China, consider India, Brazil, and Turkey) are troubled by the hard-line that Israel and the West have taken toward Tehran; and they flatly reject the use of force against it. In Israel, top former military and intelligence officials have warned that an attack on Iran would be counterproductive, and is indeed unnecessary, and public opinion polls show that most Israelis oppose a military strike.
In a word, Iran will not abruptly do something dramatic on the nuclear front that increases and solidifies the international opposition and that exposes it to a military attack. Tough rhetoric (threats to close the Straits of Hormuz) and symbolic acts (the recent naval maneuvers) plus denials of the charge that it is building nuclear weapons: that's Iran's game for now. And it won't change.
What's more probable is a slip-slide to war. How would this outcome unfold? In a word, the possibilities are (almost) endless. But the common denominator would be a series of resolve-testing actions that, while not meant to trigger war, and that are even intended to prevent it, end up doing just that.
A naval show of force off Iran that produces an inadvertent collision between warships and that is not seen by one side as an error but, rather, as a provocation, and that then leads to punitive action. Or a challenge by one side that evokes a one-upping response by another, that then... you get the picture.
Another possibility is a decision by Tehran, in the face of the growing economic crisis (as witness the plunge in the Iranian rial's value) created by the current regime of sanctions and the serial assassination of Iranian scientists, to show that it, too, can squeeze its adversaries. Think the abduction of an Israeli diplomat, which despite Tehran's denials, is traced back to Iran; or Tehran's use of pro-Iranian groups to attack Americans in Lebanon, Iraq, or Afghanistan, places where Iran has substantial influence.
In academic jargon, this slippery process is called a conflict spiral: an unintended development, or series of steps that are intended to be one-off moves to signal the other side to back off, generates a pernicious logic of its own, taking adversaries to a place none wanted to be and that leaves them distinctly worse off than they were.
So as the rhetoric soars and plans are afoot to strengthen the punitive measures against Iran, or to craft new ones, keep the lessons of the Great War and Emerson's quip in mind. Remember that what leaders intend to be individual moves could cascade and produce big, bad consequences.