“I think you will see him in favor of strong measures here, including sanctions against Russia,” a senior Rand Paul aide told me when asked how recent international events might impact Paul’s political positioning. “Unless some go far out on the path to war — calling for troops in Ukraine — I think you will see him very close to his colleagues on this issue.”

As Russia’s invasion into Crimea thrusts foreign policy back on the front page, Sen. Rand Paul, who leans toward the anti-interventionist wing of the GOP, must balance his instincts against those of a Republican Party that, since World War II, at least, have leaned hawkish.

And since the invasion, Paul has subtly shifted (in tone, at least.)

During an interview with the Washington Post’s Robert Costa, conducted on February 24, and posted on February 25 (after pro-Russian President Viktor Yanukovych was ousted, but before Russia’s invasion into Crimea), Paul said: “Some on our side are so stuck in the Cold War era that they want to tweak Russia all the time and I don’t think that is a good idea.”

(This struck me as a stark contrast to Mitt Romney’s past warnings about Russia being America’s geopolitical foe. Romney’s assessment looks prescient today, whereas one suspects Paul’s comments to the Post (about some Republicans being “stuck in the Cold War era”) might not age so well. This is the kind of thing that could, depending on how things go, wind up in a campaign ad in Iowa.)

“The Ukraine has a long history of either being part of the Soviet Union or within that sphere,” Paul continued to the Post, seeming to defend their parochial interest in the region. “I don’t think it behooves us to tell the Ukraine what to do. I’m not excited about saying ‘hey, let’s put the Ukraine in NATO’ to rub Russia’s nose in it.”

Then, he seemed to suggest that we should be more respectful of Russia — because of their nuclear capabilities. “We still need to be conscious of the fact that Russia has intercontinental ballistic missiles,” he said. “Though the Cold War is largely over, I think we need to have a respectful – sometimes adversarial — but a respectful relationship with Russia.”

Now juxtapose that with the following statement Paul made after the invasion:

“We live in an interconnected world and the United States has a vital role in the stability of that world. The United States should make it abundantly clear to Russia that we expect them to honor the December 1994 Budapest Memorandum, in which the U.S., Russia, and the United Kingdom reaffirmed their commitment ‘to respect the independence and sovereignty and the existing borders of Ukraine.’ Russia should also be reminded that stability and territorial integrity go hand in hand with prosperity. Economic incentives align against Russian military involvement in Ukraine. Russia, which has begun to experience the benefits of expanded trade with World Trade Organization accession, should think long and hard about honoring their treaty obligations and fostering the stability that creates prosperity for its citizens. Most importantly, Russian intervention in Ukraine would be dangerous for both nations, and for the rest of the world.”

To be sure, Paul’s post-invasion statement would hardly be called aggressive or hostile toward Russia. It’s not an “Evil Empire” moment. And I’m not suggesting his “before” and “after” statements contradict one another — they don’t. But he does seem to shift from chastising some Americans for being anti-Russian — to mildly chastising Putin for violating the territorial integrity of Ukraine.

Now, to some degree, this makes some sense. It stands to reason that one’s tone should change based on a changing situation on the ground. You might expect Paul to take a tougher stance toward Russia after an invasion. But the fact that I must make this point seems to illustrate his challenge.

It feels flippant to assign political winners and losers to something militaristic like this, but if such a thing exists, one would assume it would be Sen. Marco Rubio (who excels at foreign policy and rhetoric stressing moral clarity) and Sen. Ted Cruz (whom, I argue, is in the same “division” as Paul) who would benefit from foreign policy being put back on the front burner.

We are still a long way from 2016, and elections are rarely decided primarily on foreign policy, but one gets the sense that this is an issue that doesn’t naturally favor Paul.

For a few years now, a war-weary America has experienced what might be described as an anti-interventionist zeitgeist. The question is whether or not that is tenable. Republican primary voters might — depending on the world situation — return to a more traditional (for the modern GOP, at least) hawkish foreign policy. (After all, one has to assume that a certain amount of dovishness is merely an anti-Obama phenomenon.)

This poses a challenge for Rand Paul, but it sounds like he is keenly aware of that.