Restraint in US foreign policy is having a moment. That’s a good thing. But I worry it’s unclear whether restraint is a means or an end, and what that end would be. Without resolving this–preferably in favor of re-imagining a continued US leadership role in the world–current calls for restraint may do more harm than good.

The popularity of restraint in US foreign policy should be making me happy. I went to college in the Bush years, and marched against the Iraq war. After graduating, I joined a group in DC trying to formulate a smart, progressive foreign policy vision. A few years later I resigned in frustration that they accepted the troubling aspects of Obama’s foreign policy—like his expanded drone strikes—and focused mainly on helping Democrats sound tough on foreign policy. I cheered the pushback on US support for the Saudis in Yemen, beginning under Obama and continuing under Trump.

And we’re now at a moment where “restraint” is a viable stance in US foreign policy debates. Two major Democratic Presidential candidates, Sanders and Warren, are basing their foreign policy platforms on restraint. Republicans are in disarray, trying to catch up to the latest defense of the Trump Administration, but there are prominent voices for restraint in that party as well. The Cato Institute’s foreign policy team–which has pushed restraint before it was cool—is driving foreign policy debates. And we have a new think tank focused specifically on this issue, the Quincy Institute.

So why am I uneasy? Is it because I suffer from the cliched Groucho Marx joke, and don’t like having company in my convictions? Kind of. But it’s also because I worry that “restraint” has become a means and an end in US foreign policy. We need more clarity on what the purpose of this restraint will be.

Basically, if America: extricates itself from military engagements in Iraq, Syria and Afghanistan; stops funding Saudi-led fighting in Yemen; and commits to not getting involved in another military engagement that does not touch on our core interest, what will our foreign policy be?

One option is the realist dream of offshore balancing. We would keep US commitments abroad to a minimum, engaging with the world only when we are directly threatened. This would prevent another 2003, but it would also mean we won’t try to stop the next genocide (not that we really tried to stop the past ones). Such restraint would take the form of abandoning the world, which may go too far.

A more dangerous possibility is the nihilistic anti-interventionism that has found a voice in the Democratic primary. Some have opposed US military actions, getting attention from the anti-interventionist left. Yet, this anti-interventionism isn’t accompanied by a broader progressive agenda. Instead, it takes the form of downplaying the abuses of repressive states to justify the lack of US intervention. There is a risk that the restraint crowd includes such voices, coloring their policy prescriptions.

More constructive versions of restraint can be found in the foreign policy platforms of Sanders and Warren. In his “big foreign policy” Westminster speech, Sanders emphasized that a “sensible and effective foreign policy recognizes that our safety and welfare is bound up with the safety and welfare of others around the world.” And in her recent piece in The Atlantic , Warren doesn’t call from retreating from the world; instead, she wants America to focus on diplomacy, intelligence and international partnership rather than using military force as the default. Both suggest restraint, but pair it with a positive alternative to force.

But this still leaves unanswered the big question: will America still strive for leadership in the world? That is, is the goal just ending America’s military commitments, to limit harm to the world and to ourselves? Or is it also reshaping the international community so that it can function without American leadership or even involvement. This is unclear at the moment, and could cause problems for the restraint agenda.

We can adopt a restrained foreign policy and still work to coordinate international action. Both Warren and Sanders call for continued US efforts to resolve humanitarian crises and rights abuses, but instead of relying on the military we would turn first to other instruments of power. Similarly, those who express regret about US inaction on the Syrian civil war are accused of wanting to start a war, but that’s only because we saw the choice as between war and nothing; the Obama Administration could have launched a full-scale diplomatic initiative, working in the UN and with our Middle East allies to find a solution.

Likewise, we can avoid international leadership and still get involved in military engagements. The Obama Administration famously tried to “lead from behind” in the Middle East. But they did not sufficiently plan for what this would mean, and still ended up committing America to a military intervention in Libya, a vaguely defined military presence in Syria, and the aforementioned drone program. Restraint can technically include military force, just less frequently. I don’t think that’s what the restraint crowd wants.

Current calls for restraint should be accompanied by conversations on the best way to maintain US influence in the world, and ensure we can and will act to protect the vulnerable around the world. Otherwise, restraint may take a distasteful form, or never really come together. Maybe US leadership in the world will inevitably lead to overstep and military adventures, but that argument still has to be made. At the least, if the restraint crowd wants to make sure they not only transform US foreign policy, but do so in a way that is durable and constructive, they will need to address this ambiguity its purpose.