... Trump himself may or may not have anything recognizable as a strategy. Even before his inauguration, some Beltway observers were declaring him an “anti-strategic” player, who rejected not only the content of Obama-era foreign policy but the entire project of expert-driven big-picture thinking. Others, of course, have argued that Trump’s apparent lack of a strategy actually is his strategy — that he has adopted some variant of Nixon’s “madman theory” in both domestic and global affairs. According to that logic, unpredictability can be a virtue, trapping enemies and interlocutors in a reactive position, leaving them always trying to figure out what’s coming next. But even “madman theory” requires some level of planning and consistency. “Absent strategy,” Senator Jeff Flake wrote in his 2017 book, “Conscience of a Conservative,” “we are left with no theory, just the madman.”

It may be that Trump doesn’t think he needs much of a strategy, at least not for the bald task of staying in power. As the head of a party that controls all three branches of government in the world’s most powerful nation, he can flail around and contradict himself all he wants, and many people will still do his bidding. It’s those with more limited means at their disposal — a category that currently includes not only Democrats but also just about anyone else engaged in political life — who may find that strategy has something useful to offer.

The original concept of strategy comes from the world of military affairs. It derives from a Greek word meaning “generalship” or “the office or command of a general”; it was an enterprise for the man in charge. In his classic midcentury book “Strategy,” the British military historian B.H. Liddell Hart defined it as “the art of distributing and applying military means to fulfill the ends of policy,” distinguishing strategy from, on one side, “tactics” — the modes of “actual fighting” on the battlefield — and on the other, “grand strategy,” in which civilian leaders set high-level policy and coordinated the nation’s resources toward a collective goal.

For the United States, the golden age of strategic thinking is often dated to the early years of the Cold War, when big ideas like “containment” provided an overarching framework in which to make ground-level decisions. That’s when the State Department created the Policy Planning Staff under George Kennan, with the goal of taking “a longer-term, strategic view of global trends,” in the words of its current mission statement. The moment was, in many ways, tailor-made for strategic thinking. The stakes were high, the enemy was clear and the political establishment, Republicans and Democrats alike, largely agreed on the nation’s objectives; the main question was how to achieve them.

Since the Cold War, many have lamented the decline of American strategic thinking, a concern that has as much to do with the loss of clear national ends as with any shortage of means. In the public summary of his recent National Defense Strategy, designed to produce clarity of direction for the United States military, Secretary of Defense James Mattis dismissed the last few decades as an age of “strategic atrophy,” in which mighty America occupied its time swatting at regional upstarts and terrorist threats. Today, by contrast, Mattis sees a new golden age of international gamesmanship in the offing, in which “interstate strategic competition, not terrorism, is now the primary concern in U.S. national security.” The United States is, according to Mattis, still well placed to play a major role in this order, but only if it does what successful great powers are supposed to do: create and implement a consistent strategy. ...