What a cornucopia of constitutional questions is on offer in the battle looming between America and 13 states over automobile pollution standards. It has burst into the news with the decision of four automakers to defy the federal government’s efforts to relax regulation of pollution and instead bow — after what the New York Times calls “secret negotiations” — to California and other states that want to maintain tighter regulations.

This is happening as part of the resistance to the decision of the voters in 2016. They elected, in Donald Trump, a president committed more generally to rolling back overly strict environmental standards. We sense that the automobile emissions fight could end up in the Supreme Court, with a decision that, like the border wall ruling in favor of Mr. Trump, confounds the Democrats and vindicates the deep Constitution.

It reminds us, for starters, of the constitutional problem of birds. How in the feathers, you ask, can birds be a constitutional problem? It seems that they have a habit of riding the wind from one state to another. So states’ claims rest on, as Justice Oliver Wendell Holmes, Jr., once put it, “the presence within their jurisdiction of birds that yesterday had not arrived, tomorrow may be in another State, and, in a week, a thousand miles away.”

Holmes wrote that sentence in a case called Missouri v. Holland. It involved a federal game warden, Ray Holland. He was fixing to arrest some Missourians for violating a federal law called the Migratory Bird Act. The law was passed in 1918 to implement a treaty we’d struck with Canada. The Supreme Court backed Holland. It concluded that the treaty power trumps (no pun intended) state sovereignty.

This strikes us as analogous to California’s campaign to enact regulations covering particles of pollution, which travel by wind and don’t have any more respect for state borders than your average whimbrel. Except in this case things are turned around. It is not the Feds who are the regulatory hawks but rather the states. The states are more eager to regulate than the federales are. The New York Sun urges caution.

That’s because of Canada. Remember, it was to support a treaty between Canada and America that the Migratory Bird Act was written. A treaty with Canada is what gave the Feds the right to regulate birds in Missouri. It turns out that in the fight over automobile pollution, Canada has fetched up against the United States, siding instead with California.

The way the New York Times tells the story, California had been “looking for allies far and wide.” So last month, after secret talks, it signed with Canada “a clean-car deal.” The Times says it was “seen as a step” toward Canada “formally adopting the state’s standards.” It quotes one Daniel Lashhof, director of the World Resources Institute, as saying it “shows that state leadership is indispensable.”

Then again, too, it’s also unconstitutional — a prima facie violation of our parchment. That’s because of Article 1, Section 10, which lists certain powers and rights that every state gives up in perpetuity in exchange for becoming part of America. It ordains that, absent approval by Congress, no state shall “enter into any Agreement or Compact with another State, or with a foreign Power.”

Yet California confesses — in a press release no less — to doing just that. “Canada and California sign agreement to work together on cleaner transportation,” is the headline. No mention that it’s an agreement to foil a decision of America to reduce the burden placed on Americans by onerous environmental regulations. The environment just causes some people to lose their constitutional bearings.

We wrote about this two years ago, after President Trump redeemed his election promise to withdraw from the Paris Climate Accord. Mayor Bloomberg promptly launched a campaign for states and municipalities to make a separate peace with our environmental adversaries, despite the fact that the only state that is permitted to enter foreign agreements is the one of which Mr. Trump is head.