Sens. Marco Rubio and Rand Paul scored points with their respective supporters during their brief but spirited exchange over military spending in Tuesday evening’s debate.

Paul scolded Rubio for his profligate ways. “How is it conservative,” Paul asked, “to add a trillion dollars in military expenditures? You cannot be a conservative if you’re going to keep promoting new programs that you’re not going to pay for.”

Paul’s approach appealed to Katherine Timpf at National Review Online, who called it “refreshingly logical and level-headed.” The American Conservative’s Dan McCarthy praised Paul’s brand of “conservative realism.” 

Rubio, for his part, called Paul “a committed isolationist.” “The world is a safer place,” Rubio explained, “when America is the strongest military power in the world.” As sound bites go, Rubio scored. But the statement conflates the safety of the entire world with the safety of the American people. And his claim that vast increases in military spending are needed to make the U.S. military the strongest in the world imply, falsely, that it is not already. 

As I and others have noted elsewhere on numerous occasions, Rubio’s name-calling reveals the shallowness of his understanding of history and world politics. Defenders of the status quo can be counted on to shout the “isolationist” epithet whenever they want to discredit any challenges to it. Despite his relative youth, Rubio has adopted the foreign policy of men nearly twice his age. He seems blissfully unaware even of recent history. His campaign slogan calls for “A New American Century.” Sound familiar?

In terms of entertainment value, the debate was all good fun. Watching two men talk over one another on a stage was just like…watching two men talk over one another on a cable news program, complete with split screens.

But we should expect a presidential debate to be about more than crosstalk and TV ratings. So far, the candidates have largely avoided a serious discussion of the U.S. military’s roles and missions. For the most part, they reflect the elite consensus that U.S. power is essential to the functioning of the international system. Without it, the world descends into chaos. And however much power we have — our military is today the most capable force the world has ever known — it is never enough. Thus the reflexive call for more. Much more.

Rand Paul only seems an outlier relative to the interventionist class that occupies the foreign policy high ground. Credit him for speaking out early and often against the Iraq war and its progeny. Score a point for his sensible observation that “You can be strong without being involved in every civil war around the world.” Kudos for questioning those who were so anxious to arm al Qaeda’s allies in Syria, and for pushing back against the ill-conceived Libyan intervention.

On the other hand, Paul’s own proposal for increasing military spending by $190 billion over the next two years, although it is a far cry better than Marco Rubio’s call for $1 trillion in additional spending, feeds into the false narrative that the U.S. military is too small.

That is true only if one refuses to scrutinize the military’s missions, and accepts as a given that the United States must address all threats, in all places, and at all times. It only makes sense if the object is to discourage others, including our wealthy allies, from playing a larger role in their respective regions, or globally.

I hope that the next debate doesn’t merely discuss what the U.S. military must do, and what American taxpayers must pay, in order to keep the whole world safe. The next round of Paul vs. Rubio should also examine what, if anything, will be expected of others.