Eighteen months ago, environmental advocates would have been safe in assuming that the new President would choose a new Secretary of State who’s a big fan of the Law of the Sea Convention (UNCLOS).

But maybe not quite this: The new President would be Donald Trump, and his sea-hugger of a chief diplomat would be ExxonMobil CEO Rex Tillerson.

In 2012, then-Exxon boss Tillerson sent the Senate Foreign Relations Committee Chair a letter offering the oil giant’s support to renew the long-stalled push to win U.S. ratification of the Law of the Sea, a United Nations treaty designed to establish a set of rules governing oceans.

In doing so, Tillerson found himself siding with the 168 nations that have ratified the agreement, and opposing most U.S. Republicans and some Democrats who have steadfastly opposed since the 1980s due to what they see as its limiting of U.S. sovereignty—largely because Reagan-era conservatives were still cheesed off at Jimmy Carter for “giving away” the Panama Canal. To Panama.

So, let’s pause for an acid-trip of a recap: The U.S. reverses its role as an imperfect, but generally progressive force in decades’ worth of global environmental agreements on everything from commercial whaling to protecting wetlands and Antarctica in order to drag its anchor on the “Law of the Sea” treaty.

The treaty’s been in full force for years, but “full force” is close to meaningless as long as the U.S. is sitting it out. My, how things change. Senator John Kerry and other Democrats lost control of the Senate in the 2012 elections. Kerry left his Senate Foreign Relations Committee Chairmanship to replace Hillary Clinton as Secretary of State, only to be replaced by Tillerson in Trump’s 2016 election sweep.

UNCLOS has, if anything, increased in relevance, not just in long-simmering issues like regulating deep-sea fishing and mining, but in things like Putin’s lust for the melting Arctic and China’s military push via its artificial islands in the South China Sea. Those kinds of things were not on anyone’s minds when LOS came under serious discussion in the early years of the Reagan Administration.

Russia and China are both LOS signatories, but would likely blow off any LOS rulings that could limit their ambitions. And by sitting the treaty out, the U.S. has no leverage to do so.

Also curious is the parade of GOP secretaries of state and captains of industry who have supported LOS ratification: Henry Kissinger, Colin Powell, Condoleezza Rice, the National Association of Manufacturers, the U.S. Chamber of Commerce, and more. Mind you, none of them, Tillerson included, have done so for the same reasons as enviro advocates.

But both see the U.S. as a player in the Law of the Sea as giving a leg up to American stature to protect the oceans. Or exploit them.

Could Rex T grant an enviro wish? It’s a mystery. Certainly, the Secretary of State’s near-absence from the current, even-bigger diplomatic row—North Korea’s hydrogen bomb hissyfit—isn’t encouraging.

He’s the dude with the diplomacy, but the U.S. is answering North Korea via the dudes with the bombs—President Trump and Defense Secretary “Mad Dog” Mattis. No shocker here, but Trump has been sending out at least a few environmental signals that are downright bipolar.

His new NASA Administrator pick, Oklahoma congressman Jim Bridenstine, is widely seen as a protégé to uber-denier Senator Jim Inhofe and therefore a threat to NASA’s substantial work on climate change. Bridenstine is on record as supporting NASA’s deep-space work, however.

Trump’s nominee for the #2 slot at NOAA is a veteran Navy oceanographer who favors action to curb global warming. Retired Rear Admiral Tim Gallaudet sees a strong role for the agency in climate science.

So we’ll see.