Yet despite the overwrought claims of Gelb (and others) that America’s very survival is today at risk, the present historical moment lacks comparable clarity. Ours is not a time when we face a single overarching threat. Instead, on several different fronts, worrisome developments are brewing. Environmental degradation, the rise of China and other emerging powers, the spread of radical Islam, the precarious state of the global economy, vulnerabilities that are an inevitable byproduct of our pursuit of a cyber-utopia: all of these bear very careful watching. Each one today should entail a defensive response, the United States protecting itself (and its allies) against worst-case outcomes. But none of these at the present moment justifies embarking upon a let-out-all-the-stops offensive. Chasing after one problem would necessarily divert attention from the rest.

The immediate future remains too opaque to say with certainty which threat will turn out to pose the greatest danger, whether in the next year or the next decade — and which might even end up not being a threat at all but an unexpected opportunity. Conditions are not ripe for boldness. The abiding imperative of the moment is to discern, which requires careful observation and patience. In short, forget about strategy.

And there’s a further matter. Correct discernment assumes a proper vantage point. What you see depends on where you sit and which way you’re facing. Those who inhabit the upper ranks of the Obama administration (and those whom Leslie Gelb offers as replacements) sit somewhere back in the twentieth century, their worldview shaped by memories of Munich and Yalta, Korea and Vietnam, the Cuban Missile Crisis and the Berlin Wall, none of which retain more than tangential relevance to the present day.