For a bull in the china shop, President Donald Trump has so far gingerly stepped around the Paris climate accord. That dance could end as soon as this week, with Trump deciding whether to stay in or opt out.

“Out” should be the obvious answer. No U.S. interest is served by remaining part of the accord, which even its supporters say is mostly an exercise in window dressing — that is, when they aren’t insisting that the fate of the planet depends on it.

The treaty’s advocates, hoping to forestall a Trump exit, are trying to save the accord by arguing that it is largely meaningless. In this spirit, a piece on the liberal website Vox explained, the Paris accord “asks participants only to state what they are willing to do and to account for what they’ve done. It is, in a word, voluntary.” In other words, “Nothing to see here, just us climate-change alarmists playing pretend.”

And there is indeed much to be said for the worthlessness of Paris. Beijing pledges that China’s emissions will “peak around 2030.” By one estimate, this is when its emissions would peak regardless. So the world’s largest emitter is using the accord as a platform for climate virtue-signaling.

According to Benjamin Zycher of the American Enterprise Institute, even if Paris is fully implemented and you accept the Environmental Protection Agency’s model for how emissions affect warming, it will produce a rounding error’s worth of decline in the global temperature by 2100 — .17 of a degree Celsius.

If Paris is such a nullity, why shouldn’t we simply pull out? This is where its supporters reverse field and contend that it will be a global disaster if the U.S. leaves. Supposedly the moral suasion involved in countries coming up with voluntary targets and having to defend their performance meeting them will drive an ever-escalating commitment to fight global warming.

Once upon a time, Paris was portrayed as a tool for steadily tightening restrictions on fossil fuels. The Obama team referred to one provision in the accord as “ratcheting up ambition over time.”

Whatever their opportunistic salesmanship at the moment, this clearly is still the goal of the treaty’s supporters and a reason why Trump should get out while the getting is good. International agreements acquire a dead-weight momentum of their own. Witness how hard it is to pull out of the Paris accord now, when it went into effect only last November. In another couple of years, it will acquire the sanctity of the Peace of Westphalia.

The treaty may be notionally voluntary, but climate-change activists will surely hunt for a judge willing to find a reason that the U.S. emission target in the accord is binding. Trump’s unhappy experience in the courts with his travel ban should make him highly sensitive to this judicial threat.

In the context of Trump’s handling of other international agreements, getting out of Paris shouldn’t be a close call. To have pulled out of the Trans-Pacific Partnership — a free-trade agreement with tangible strategic benefits in Asia — and stay in Paris would be a travesty. To irk our European allies with less than explicit restatements of our commitment to NATO, then placate them by standing by Paris, would be strategic folly.

The shrewdest option would be to submit the agreement to the Senate for ratification, where it certainly would be rejected. President Barack Obama pretended that the treaty was an executive agreement — even though it involves 195 countries, and purports to bind future U.S. presidents — precisely so he could do an end run around the Senate. Honoring the Senate’s constitutional role in considering such a treaty would make it that much harder for the next Democratic president simply to sign on again unilaterally.

Failing that, Trump should say farewell to Paris on his own, and never look back.

© 2017 by King Features Syndicate