What are Rand Paul’s biggest assets as he attempts to convert the GOP into an isolationist party? He has several, and one of them is John McCain.

McCain surely is among the names Paul “didn’t need to mention” when he declared before CPAC that “the GOP of old has grown stale and moss-covered.” Paul also didn’t perceive a need to name the GOP policies he believes are stale. Instead, he followed that shot by talking about the importance of getting government “off our backs” — a worthy goal, but one that Republicans long have stood for.

Better for Paul to remain vague about his policy differences with the “old GOP,” ride his current wave of popularity, and allow Republicans to give him the benefit of the doubt as they fill in the blanks. Better for Paul to present himself as the antithesis of McCain — who advocates a strong defense and U.S. engagement overseas but is unpopular with Republicans for very different reasons — than openly to advocate sharp reductions in defense spending and U.S. disengagement from the world.

At times, Paul is less coy about his desire for the U.S. to disengage. Bill Kristol points out that in a recent interview, Paul commended Joe Biden for saying during the vice presidential debate that “we’re coming home.” Paul continued: “I think that’s what people want; I think that’s what people are ready for, that we’re coming home.”

Even here, Paul was being a bit coy. His isolationism almost surely exceeds what Joe Biden has in mind. Even Biden’s boss does not entirely eschew the possibility of serious U.S. engagement in the Middle East, albeit not with boots on the ground. And one can imagine circumstances under which Biden might favor “leaving home” to fight terrorism or to oppose out-and-out aggression.

I have never heard Paul say anything that provides even a modest level of comfort on these scores. From all that appears, Paul understands “coming home” not as a description of our policy towards Afghanistan, but as a broad prescription for American defense and foreign policy in general. In other words, he means it in the McGovernite sense at best, and more likely in the Ron Paul sense.

Fortunately, as Krisol reminds us, there are fresh conservative voices that uphold the traditional Republican position on the need to protect America from its enemies:

It fell to a freshman congressman, speaking at CPAC on the same day as Rand Paul, to tell some hard truths. “I know there is war weariness among the American people, just like there is war weariness among conservatives, and in this audience, no doubt,” said Tom Cotton from Yell County, Arkansas. “It’s no surprise, though, that the American people are war weary when their commander in chief is the weariest of them all.” But, Cotton reminded his audience, “We’re fighting . . . a war against radical Islam and jihad.” He continued, “Our president often says 10 years of war are ending. Wars are not movies. They do not end. They are won or they are lost. The quickest way to end a war is to lose it.” And Cotton pointed out the obvious: “We have the manpower to win the war. We have the matériel to win the war. The question is, do we have the most essential element to combat power? Do we have the will to win the war? Our enemies certainly have that will. They question now whether we do.” Cotton is 35 years old. He’s not stale or moss-covered. A combat veteran, he understands real war weariness. But he also understands it needs to be resisted and overcome. Above all, he understands, as did the GOP of old, the GOP of Nixon, Reagan, and Bush, that while we may not be interested in war, our enemies remain interested in us. And so, Cotton concluded his remarks, “We as conservatives must have the will to win.”

In the current moment, Rand Paul can thrive politically as an isolationist by remaining vague and by drawing favorable, general comparisons between himself and John McCain (without naming him, of course). But this strategy won’t remain viable as 2016 approaches. Although that election may come too soon for Tom Cotton, it will arrive too late for John McCain.

If Paul wants to demonize anti-isolationists during the primary season, he probably will have to attempt this at the expense of, say, Marco Rubio and/Paul Ryan. That clash won’t feature the old vs. the new. It will feature the responsible vs. the smugly complacent.