When Jim Webb announced that he is thinking seriously about running for president in 2016, it didn’t exactly excite hearts and minds in the Beltway. The former senator from Virginia is widely regarded as an odd duck who stubbornly goes his own way. He dropped out of electoral politics after one term in the Senate and resumed his successful career as a writer. Webb’s bestselling novel Fields of Fire captured the reality of the Vietnam War, in which he had fought as a Marine platoon leader.

Wounded twice in battle, Webb was awarded the Navy Cross for extraordinary heroism. After the war, he wrote scholarly studies on war and national defense. Ronald Reagan appointed him secretary of the Navy, though Webb is a working-class Democrat, descended from hardscrabble country people in Arkansas.

Instead of becoming more hawkish, as defense intellectuals often do when they acquire status and influence, Webb has become increasingly critical of how US military force is used and misused. His biography is what gives his candidacy potential significance. It is not that he has much likelihood of winning the nomination, but Webb has a chance to do something far greater for the country. Given his résumé and valor in war, Webb has the authority (and the guts) to provoke a profound national debate about the nature of US militarism.

Webb’s unique perspective may be familiar to political insiders or readers of his books, but they probably aren’t to the broad public. Six months before George W. Bush’s invasion of Iraq, Webb prophetically warned against it. “Those who are pushing for a unilateral war in Iraq know full well that there is no exit strategy if we invade,” Webb wrote in The Washington Post. In 2004, Webb called Bush’s war “the greatest strategic blunder in modern memory.” Ten years later, he is still right.

In 2007, Chris Matthews dubbed him “the antiwar warrior.” That’s a clever label, but it fundamentally misconstrues Webb’s position. He is not a pacifist—that is, he is not against wars fought to defend against real threats to the nation. What Webb opposes are the reckless and limitless interventions that the United States has initiated during the post–Cold War era of the past decades.

Presidents of both parties, including Barack Obama, have strayed from the old principles. “It is not a healthy thing when the world’s dominant military and economic power has a foreign policy based on vagueness,” Webb observed. He had in mind Bush, but also Obama’s vague purpose in entering the bloody civil war in Syria. “There is no such thing,” Webb has asserted, as “humanitarian war,” a feel-good concept popularized by some of Obama’s national security advisers. Webb has not challenged the president’s authority to bomb Syria, but says “the question of [Obama’s] judgment will remain to be seen.”

Webb has laid down principles for foreign interventions that probably would have kept the United States out of some wars if political and military leaders had listened to him. “An important caveat on how our country should fight the terrorists if they are a direct threat to our national security is: do not occupy foreign territory.” Another Webb warning: “Never get involved in a five-sided argument.” Obama has stumbled into one in the Middle East, unable to state firmly who is our ally and who is our enemy.

A glimpse of Webb’s broader intellectual framework can be found online in the stirring book review he wrote for The American Scholar in praise of historian Andrew Bacevich’s seminal work The New American Militarism: How Americans Are Seduced by War. Bacevich and Webb disagree on some points, but they are kindred spirits. Both served in Vietnam, and both have sons who went to war in Iraq (Bacevich’s son was killed there).

Webb saluted Bacevich’s book for describing the confusion and corruption of military values that followed Vietnam and for revealing the profound confrontation within the military institution itself. “One side,” Webb explained, “is represented heavily by those with a classical training in America’s past wars (and frequently with experience in having fought them), who would send American forces into harm’s way only if the nation is directly threatened. The other side is dominated by a group of theorists, most of whom have never seen the inside of a military uniform, who adhere to an essentially Trotskyite notion that America should be exporting its ideology around the world at the point of a gun.”

This buried conflict in national purpose is the essence of America’s dilemma in the world—a self-made trap in which the nation can neither win the endless, borderless conflicts nor get free of the impossible obligations claimed for the US military. As a presidential candidate, Webb would be uniquely positioned to bring this confrontation out of the shadows. He could teach people how to understand the real choices America faces in its foreign policy and national defense.

Webb’s ideas may sound old-fashioned, but they are actually about changing the future. In the broad sweep of American history, this is often how fundamental change has occurred. Disruptive new thinking does not usually come from the top down, but more often is put in play by fearless individuals like Webb who think for themselves and are sure the people will be with them once they understand what’s at stake. This requires political skills that Webb may or may not have. How does he make himself heard if big media ignores his message?

Jim Webb is probably not going to become our next president. But he has the possibility of becoming a pivotal messenger. I think of him as a vanguard politician—that rare type who is way out ahead of conventional wisdom and free to express big ideas the media herd regards as taboo. With luck, the country might have two such characters in the 2016 primaries: Jim Webb and Bernie Sanders. In different ways, both are expressing unsanctioned ideas that Americans need to hear.

If you follow media chatter, the 2016 contest is already decided for Democrats. The people are ready for Hillary, we are told repeatedly. She has staked out a pro-war position more hawkish than the president’s but smartly aligned with the public’s current enthusiasm for continued bombing in the Middle East. But how might folks feel two years from now? Will they turn against war and warrior politicians if this new war also begins to seem interminable?

Albert Hunt of Bloomberg, a wise old head in the Washington press corps, offered this forecast: “Jim Webb could be Hillary Clinton’s worst nightmare.”