The headlines announce: “Fox Business moderators pledge ‘real debate’ in Milwaukee.”

That won’t happen. Several candidates who have attempted to engage in serious debate about key issues have been excluded from Tuesday night’s main-stage debate and shunted off to the low-profile “undercard” match. Candidates who have been thoughtfully and consistently critical of front-runner Donald Trump are excluded altogether. And there will be a desperation factor in Tuesday’s Milwaukee debate, as several of the remaining contenders are teetering on the edge of oblivion.

That’s especially true of Kentucky Senator Rand Paul.

Paul is getting what may be his last chance to debate on the main stage of a Republican presidential debate. On Tuesday, he will be on the edge of the stage for the Fox Business News/Wall Street Journal debate featuring front-runners Trump and Dr. Ben Carson and a crew of potential also-rans who are trying to get traction. At this point, Paul is closer to the edge than the others. In fact, he was running even with former Arkansas Governor Mike Huckabee in the latest Fox News poll, and behind New Jersey Governor Chris Christie in the latest Quinnipiac poll—and both Huckabee and Christie have, based on the average of four recent polls, been bumped from the main-stage debate.

So this is make-or-break time for Paul, who like Huckabee and Christie has actually distinguished himself from the rest of the field on some critical issues. Obviously, in this year of personality-over-substance politics, issue distinctions count for less than they historically did. And in the ridiculous debates so far, issue distinctions have counted for even less because the moderators tend to ask so many interview-style questions—rather than highlighting genuine differences of opinion among the contenders.

But Paul has a real chance to stand out on Tuesday.

President Obama has handed Paul an issue, and the Republican should seize it.

Two days after the last Republican debate, Obama reversed his own opposition to putting boots on the ground in Syria. The president decided to send US Special Operations troops to that country. He has done so without adequate congressional authorization, despite the fact that, as Congressman Peter Welch, Democrat from Vermont, says, “Make no mistake about it, this is a war.”

What Congresswoman Barbara Lee refers to as “escalating mission creep in Syria” has divided Democrats. Former secretary of state Hillary Clinton’s campaign says she “sees merit in the targeted use of special operations personnel to support our partners in the fight against ISIS, including in Syria,” while Senator Bernie Sanders “believes that the crisis in Syria will be solved diplomatically, not militarily.” Sanders sides with President Obama in opposing what the Vermont senator refers to as “a unilateral American no-fly zone in Syria, which could get us more deeply involved in that horrible civil war and lead to a never-ending U.S. entanglement in that region.” So does former Maryland governor Martin O’Malley. Clinton backs the no-fly zone.

Republicans Ben Carson, Jeb Bush, Marco Rubio, Carly Fiorina, John Kasich, Lindsey Graham side with Clinton on the question, while Chris Christie goes a step further—saying that, as president, he would order the shooting down of Russian warplanes. Donald Trump favors a vague “safe zone.” Ted Cruz is a no-fly-zone skeptic but says that, as president, he would dispatch US ground troops “if need be.”

For the most part, the Republican contenders scramble to outdo one another in a competition to position themselves as hawkish militarists who are ever at the ready to deliver bombastic statements about next wars.

Paul is different. Though he is not quite so anti-war as his father, former congressman and presidential candidate Ron Paul, the senator has made it clear that he opposes dispatching troops to the region. “The fighting on the ground needs to be done by the people who live there,” says Rand Paul. “The Sunnis will have to rise up and say ‘enough is enough.’”

In mid-October, Paul ripped his fellow Republicans for their misguided militarism.

“I think we should talk about politics for a minute,” the senator said. “Shouldn’t we at least talk about what idiots we have in the Republican Party running for president who want to have a red line and a no-fly zone in Syria. What a recipe for disaster. But you know what the interesting thing is, Hillary Clinton agrees with all of them. All of them beating their chest to see who is the most likely to get us involved in a war that really, these people have been at war for a thousand years. You think somehow we’re going to solve their problems?”

That’s the Rand Paul who should show up at the debate Tuesday.

The senator should seize the opportunity to distinguish himself from his fellow Republicans on issues of war and peace. It ought to be the focus of his opening statement, and of responses to questions. There’s a good chance that the issue of Syria will arise directly. If it does not, it can surely be addressed in response to broader questions about foreign policy, budgeting and priorities.

This is good policy, and good politics—as polls suggest that there are plenty of Republicans who share the skepticism of Democrats when it comes to sending US ground forces into Syria and Iraq. Indeed, as Robby Soave, a staff editor at the libertarian-friendly website Reason.com, notes, “This is the side of Paul libertarians want to see more of—particularly in the debates. Voters who think it’s a good idea to get involved in the Syrian civil war have plenty of candidates on both sides of the aisle to choose from. On the other hand, voters who are skeptical that further military intervention in the Middle East could possibly be the right course of action have few options. Paul must court them.”

Paul has to understand the political necessity of distinguishing himself from the field in order to maintain his viability as a presidential contender. And he has a chance to do so on an issue that sincerely concerns him: US military adventurism.

And this is not just about Paul and the Republicans. Democrats and independents who care about questions of war and peace should hope that they are debated generally—and that issues of congressional oversight are raised whenever the country is drifting into new conflicts. It is not necessary that Americans be enthusiastic about Rand Paul or his candidacy—and he has certainly taken plenty of positions that will argue against that candidacy—to recognize that there is a need for more debate on these issues. The growing US presence in Syria ought to be a central issue when Republicans debate, just as it ought to be a central issue when Democrats debate.