This is newsy not in the sense that Rand’s said anything new and shocking on the subject but more in the sense of “wow, these primary vulnerabilities sure are piling up, aren’t they?”

Make no mistake, Paul is not a climate convert. He has questioned the validity of climate science and left plenty of rhetorical room to oppose environmental policy. Paul also has called the pillar of Obama’s second term climate agenda—regulations to rein in carbon emissions from power plants—an “assault to our economy” and vowed to roll back the regulation.

But in recent months, Paul has indicated that human activity is contributing to climate change and suggested support for cutting emissions…

Paul also sees an upside to environmental regulation in some cases. “I’m not against regulation. I think the environment has been cleaned up dramatically through regulations on emissions as well as clean water over the last forty or fifty years, but I don’t want to shut down all forms of energy such that thousands and thousands of people lose their jobs,” Paul said during a November interview on HBO with Bill Maher…

“This is a packed field so we’re going to see people using anything they can to discredit each other. I could see Cruz, Rubio and others playing Whac-a-Mole with this,” said Ford O’Connell, a Republican strategist and former campaign advisor to John McCain. “There’s very little upside to sticking your neck out so soon on this.”

Remember this from last month?

These 15 Senate Republicans voted YES Hoeven amendment stating "human activity contributes to climate change": pic.twitter.com/mncX7z9lSQ

— Frank Thorp V (@frankthorp) January 21, 2015

Paul was the only GOP presidential candidate-in-waiting willing to roll the dice on that one (no, Lindsey Graham doesn’t count), although he did vote no on another amendment that asked whether human activity “significantly” contributes to climate change. Why would an aspiring tea-party candidate who already has potential problems with his base on foreign policy and voter ID risk defying them on another litmus-test issue like climate change? Maybe Rand’s (foolishly) looking past the primary to the general election, knowing that Democrats will run an all-out “Paul’s a crank” campaign against him. The more centrist credibility he can bank with initiatives like drug-sentencing reform and rhetorical concessions to man-made climate change, the harder it’ll be for Hillary to crank-ify him.

But c’mon: Given how insanely competitive the primaries will be, how likely it is that Paul’s looking past them? There has to be a primary strategy to this too. Remember this poll from a few weeks ago?

Fifty-two percent of Republicans now acknowledge a scientific consensus that climate change is mainly man-made? Hmmmm. Any other polls support that unlikely possibility? Actually, yes — this one from the NYT last month has lots of surprising results among Republicans. A taste:

Another hypothetical answer, in which the candidate answers a la Marco Rubio that he’s not a scientist and doesn’t know what’s causing global warming, drew a split of just 37/26. Another taste:

When asked how serious a problem global warming will be for the U.S. if nothing is done to reduce global warming, 53 percent of Republicans said “very” or “somewhat” serious. But … how can that be when it’s basic conservative orthodoxy by now that, at best, the effects of climate change are being wildly exaggerated by the left to advance their regulatory agenda? I think Pew explained that in November 2013:

A solid 61/30 majority of non-tea-party Republicans thinks there’s solid evidence that the Earth is warming, although they split on whether the cause is man-made or natural. Among tea partiers, an even more solid majority of 25/70 says there’s no solid evidence to believe that warming is occurring, let alone what’s causing it. What we’re seeing within the GOP, in other words, is another establishment/conservative schism opening up on a hot-button issue, a la amnesty and gay marriage. There probably is momentum, as the polls above suggest, within the party towards believing that global warming is happening and that man is responsible (the same Pew poll noted above showed a 15-point increase in support among Republicans since 2009 for the proposition that the Earth is warming) — but most of that movement is happening among the center-right. Take note, Jeb Bush.

Which brings us back to our main question. Why would a tea partier like Rand Paul choose to move left on climate change, knowing that his would-be base is the party’s redoubt of global-warming skepticism? The answer, I think, is that Ted Cruz’s increasingly likely candidacy has convinced Rand that votes will be harder to come by on the right than he thought so he should make a stronger play for the middle. Thanks to his dad, he’s the only candidate in the field who’ll have a sizable base uncontested by any other candidate waiting for him once he jumps in. If he starts with, say, 10-15 percent support by locking up libertarians, all he has to do to contend in Iowa and New Hampshire is find another 10-15 percent somewhere. He’ll get a few tea-party votes from righties who dislike Cruz but maybe at this point he thinks there’s more upside in the middle from people who don’t want a doctrinaire conservative nominee but also don’t want another Bush presidency. Moderation on climate change, like moderation on foreign policy and support for criminal-justice reform, is Rand’s way of signaling to those voters to give him a look.