American eyes have been riveted on North Africa and the Middle East these past months. The popular protests that rocked Tunis, Cairo, and Tripoli, and so many other cities during the "Arab Spring" of 2011 evoked memories of the violent confrontation between Iranian dissidents and President Mahmoud Ahmadinejad's Islamist regime in the streets of Tehran eighteen months earlier.

As in Tunisia and Egypt, Facebook and Twitter helped spread the word in June 2009 that Iran was teetering on the brink of revolution, and as in Libya, the ruling elite cracked down instinctively with brutal force. Unlike Libya's Muammar Qaddafi, however, Ahmadinejad stopped short of unleashing the Iranian air force against his opponents.

Yet, some Americans nevertheless expected that Iran's recent quest for nuclear weapons, its support for Islamic radicals like Lebanon's Hezbollah, and its destabilizing influence on the geopolitics of the Persian Gulf would eventually require U.S. military intervention.

Speaking off the record, one of President Barack Obama's top advisers recently confirmed that the Tomahawk missiles that the U.S. Sixth Fleet launched against Libya were also intended to send a message to Iran.

In fact, relations between the United States and Iran have been complicated and edgy as long as anyone can remember.

America's initial diplomatic encounter with Iran, or Persia, as it was called a century ago, did not go well.

On 9 March 1904, Kurdish bandits robbed and murdered Benjamin Labaree, a 38-year-old American missionary, not far from Mount Ararat in the no man's land just inside Iran's border with Ottoman Turkey.

Outraged by what the U.S. ambassador labeled an act of "religious and race hatred," the State Department demanded that Shah Mozaffar al-Din arrest the killers, pay Labaree's family an indemnity of $50,000 in gold, and assure "the civilized world" that Iran would prevent such atrocities in the future. Although the Shah of Iran was insulted by Uncle Sam's impertinence, he had little choice but to accept the U.S. demands.

Over the following decades, time and again a constantly shifting cast of Iranian and American leaders would butt heads over issues as diverse as oil wells, religion, and atomic bombs.

Much has changed over the years, of course, but to a very great degree, the United States and Iran today still frame their mutual antagonism as a clash between civilization and barbarism, much as they did when Benjamin Labaree was gunned down in a mountain pass 500 miles northwest of Tehran in 1904.

Oil and the Fate of Modern Iran

At the dawn of the twentieth century, Americans would have recognized Iran as an important imperial buffer between Russia and India, twice the size of Texas and famous mainly for exporting Persian rugs.

Then in 1901, the British-owned Anglo-Persian Oil Company secured an exclusive concession from Shah Mozaffar al-Din and his Qajar dynasty. Seven years later, the firm discovered a huge pool of petroleum at Masjid al-Suleiman in southwestern Iran, and the future of that country was transformed.

After World War I erupted in 1914, Anglo-Persian would satisfy the Royal Navy's rapidly expanding appetite for diesel fuel by pumping oil from the world's largest refinery at Abadan, near the headwaters of the Persian Gulf.

Mozaffar al-Din's successors accepted the small but steady stream of royalties that flowed into their coffers until 1925, when Reza Khan, an Iranian cavalry officer, overthrew the Qajars, proclaimed himself Shah, and established the Pahlavi dynasty.

A hard-headed nationalist, Reza Shah tried unsuccessfully to seize control of the oilfields from the recently rechristened Anglo-Iranian Oil Company (AIOC) in 1932 and flirted with Nazi Germany later that decade in an ill-advised effort to counterbalance Britain's influence. Troubled by the specter of a Berlin-Tehran axis, Winston Churchill and Josef Stalin secretly agreed to depose Reza Shah in August 1941, replacing him with his 20-year-old son Mohammed Reza Pahlavi. They also announced that their two nations would jointly occupy Iran for the duration of World War II—Britain in the south and Russia in the north.