Osama bin Laden’s body had barely hit the water before people were predicting the impact his death would have on the war in Afghanistan, U.S. relations with the Islamic world and President Obama’s reelection campaign. The only problem with these immediate statements is that events are unlikely to work out the way anybody expects right now.

That has been the historic pattern. With events like this, unforeseen consequences have been the norm.

When 53 Americans were taken hostage in the U.S. Embassy in Iran in 1979, the most oft-heard prediction was that the humiliating spectacle would give a huge boost to Sen. Edward M. Kennedy’s drive to deny President Carter a second term. Instead, the country rallied around its commander in chief....

...[I]t was a short-lived boost and his approval numbers were down to 31 percent by November. Republican Ronald Reagan later would be able to cite that rescue failure as an embarrassing example of what he called “the hollow military.” But very few of the “experts” at the time foresaw the political impact of Iran on Carter....