Jackson Lears teaches American history at Rutgers University. He is the editor of Raritan: A Quarterly Review and the author, most recently, of "Rebirth of a Nation."

Within the Washington political consensus, “isolationist” has long been a synonym for naïve, scared, xenophobic—or all three. No politician who wants to be taken seriously at the national level can afford to be tarred with that brush. From the left, isolationism exudes the sickly-sweet smell of sentimental pacifism; from the right, the acrid aroma of ethnocentric nationalism. Either way, it leaves a stench in the halls of the foreign policy establishment. Isolationism is a bipartisan epithet that gets deployed on Capitol Hill whenever cuts in military spending are contemplated or critiques of overseas intervention are voiced....

...[N]ot even Obama has been immune to charges of isolationism. In a 2011 speech announcing his plans for withdrawing troops from Afghanistan, Obama said: “Over the last decade, we have spent a trillion dollars on war, at a time of rising debt and hard economic times. Now, we must invest in America’s greatest resource—our people.” This anodyne statement marked “The President’s Isolationist Turn,” according to an article by former Bush speechwriter Noam Neusner, who claimed that those words “could have been written by an isolationist of the early 20th century.” If even Obama can be tagged with this label, then surely it deserves some critical scrutiny. One might start by asking: Just what did isolationists think—and say—in the early twentieth century?

Christopher Nichols provides some provocative answers to that question in Promise and Peril, which is far more intellectually venturesome than its textbookish title suggests. Nichols has written a rediscovery of the isolationist tradition, a thorough and timely account of thinkers as diverse as William James, W.E.B. Du Bois, Randolph Bourne, Eugene Debs and Jane Addams. The book is not flawless: its workmanlike prose contains the occasional misplaced modifier, and at least one quotation is repeated within a page of its first appearance. Also, in his arguments Nichols sometimes makes the isolationist tradition so capacious as to lose its basic coherence, such as when he includes the imperialist Henry Cabot Lodge, whose sole isolationist credential was his opposition to any abridgment of national sovereignty by the League of Nations. Still, Nichols has accomplished a major feat, demonstrating that isolationism was a far richer and more complex intellectual tradition than its critics have ever imagined—one that still speaks to our own time, freshening the stale formulas of the Washington consensus and allowing us to reimagine the role of the United States in the world....