I raise the question because it is clear that, in recent months, President Bush has been confronted with one variety of that dilemma. He had been assured by our intelligence agencies, over many months, that Teheran was working energetically to build a nuclear weapon, and would achieve that goal in a specified (small) number of years. This assumption has been a key factor in developing U.S. policies toward Iran -- as, Lord knows, it ought to have been.
Now, according to The New York Times, these same intelligence agencies state, on the basis of new information, that Iran's leaders decided "in late 2003 to shut down a complex engineering effort to design nuclear weapons." If this is true, the United States has been proceeding, for four years, on dangerously mistaken assumptions about Iran -- assumptions that might well, at any point, have misled a cautious president into a wholly unnecessary war.
What should George W. Bush do now? Kick off his shoes, put his feet up, and say, "Well, now we know the previous intelligence was false."? Or ignore the new information, and play it safe by continuing to act in accordance with the worst-case scenario?
I can see no easy solution to the problem. Bush must decide whether to discount the encouraging reports and keep America focused on the possible danger of a nuclear-armed Iran, or accept the new information as true and let down our guard accordingly. Either way, he will be pilloried by history (never mind the Democrats!) if he guesses wrong.
Aren't you glad you aren't president?