Right up until Joe Biden announced that he is not running for president, mainstream media deemed to be of significance the advice that he had given President Obama about whether to attempt the raid that killed Osama bin Laden in 2011. This was seen as a measure of the relative judgment that he and another adviser to the president at the time, then-Secretary of State Hillary Clinton, exhibited. Clinton has received kudos for reportedly being firmly in favor of an operation that achieved its immediate objective and is widely regarded as a major success; the advice Biden gave evidently is more uncertain. But whether each one voted yes or no while this operation was being discussed by the president's senior advisers in the Situation Room—with our giving more points in hindsight for a “yes” than a “no”—tells us much less about the presidential level of judgment that each was demonstrating than many seem to think it does. Using an episode such as this as a gauge of fitness for high office is another instance of the all too common practice of rating leaders in large part for events that are outside their control, rather than reserving praise or blame for things that are more in their control and that are better measures of good or bad judgment.

Based on what we know about the decision to go after bin Laden—and some journalists have been telling us that we may not know as much as we thought we knew—there were important things that the president himself and his advisers evidently did not know, beginning with whether bin Laden was for certain in the house that would be raided. The decision was not a straightforward matter of applying good judgment to known facts but instead a matter of taking a risk. Insofar as a president needs to take some risks to get things done, Mr. Obama deserves credit for being willing to take this one, but that evaluation should not depend on the particular outcome that the operation happened to have.

The operation easily could have gone wrong in several ways, and not just if bin Laden had turned out not to have been in the targeted compound. There could have been mishaps in the movement of the U.S. forces involved that would have prevented completion of the mission. Worst of all would have been a violent altercation with Pakistani forces. If any of these outcomes had materialized, then the operation would have been widely regarded as a failure, it would have been seen as a black mark for the president and his advisers, and association with the decision to attempt the raid would be seen as a political liability rather than an asset. But notwithstanding these public perceptions, the judgment represented by the advisers' recommendations would not actually have been any different than with the outcome that actually occurred.

Compare this with a daring U.S. operation that turned out to be a failure: the attempt in 1980 to rescue Americans held hostage at the U.S. embassy in Tehran, an incident usually remembered under the label Desert One. The failure resulted directly from very specific, down-in-the-weeds military mishaps: mechanical failure of helicopters and a fatal collision between two of the U.S. aircraft at the desert rendezvous site. Such happenings are not the stuff of presidential judgment. A president can press his military commanders about whether they have been thorough enough in their planning and preparation, and he can include in his own decision-making a fudge factor for how even the best-laid plans sometimes go awry, but beyond that he essentially has to leave much to chance as far as his own role is concerned.

Desert One was regarded as a low point in Jimmy Carter's presidency, and Carter himself singled out the failure to gain freedom of the hostages as the biggest reason he was defeated for re-election. But if Barack Obama deserves credit for making a gutsy, risky decision with the operation against bin Laden, then Carter deserves comparable credit for a gutsy decision to attempt the rescue in Iran. If the aircraft failures in the Iranian desert had not occurred and the operation succeeded in bringing the hostages home, the whole episode would have been perceived as a shining success and Carter's political stock would have risen significantly. But again, we really would not be justified in making an evaluation about Carter's judgment being good or bad that is any different with this counterfactual outcome of the operation from whatever evaluation of his judgment should be made given the actual outcome.

Giving inappropriate credit or blame to the person at the top for these sorts of unpredictable variations in the outcome of U.S.-initiated operations is a subtype of the larger tendency to assign credit or blame for unpredictable things in general, including ones the United States does not initiate, such as terrorist attacks. This issue has come up again with Donald Trump's assertions about George W. Bush and 9/11. Trump's accusations are inappropriate because no matter how soundly an administration may have assessed an underlying terrorist threat and attempted to respond to it, that is different from being able to detect and prevent a specific terrorist operation.

It is with the larger matters of assessing threats and setting strategic direction that we can confidently and appropriately evaluate presidential judgment. We should not blame George W. Bush for the occurrence of 9/11, but we can charge him with bad judgment for misunderstanding and/or twisting the nature of the underlying threat such that it somehow got translated into a problem with Iraq. He, and his most influential advisers, displayed atrocious judgment in initiating a war in Iraq. That war turned out to be such a costly mistake not because of unpredictable, tactical occurrences—and not for any reason having to do with the presence or absence of weapons of mass destruction. It had a very bad and costly outcome for reasons involving the political culture and political demography of Iraq and the limitations of military force. Those reasons were not only knowable but known, to experts inside and outside government, but Bush and his advisers did not avail themselves of that knowledge.