Opinion: The United States is skipping COP31. The rest of the world will still write the rules.

When the United Nations climate summit opens Monday in Antalya, Türkiye, nearly 200 countries will send negotiators to argue over the financial architecture that is supposed to carry the world's response to a warming planet through the next decade. The United States will not be one of them. For the second consecutive annual conference, and the second time in a decade, Washington will not have a delegation inside the negotiating rooms where the rules are actually written. What will arrive instead is a planeload of members of Congress, fresh off an election that just handed their party control of both chambers, hoping that a show of diplomatic goodwill can stand in for a seat at the table. It cannot, and the gap between the two is the real story of this COP.

A second empty chair

The summit, known as COP31, runs from November 9 to 20 at the Antalya Expo Center, with a World Leaders' Summit set for its opening days, according to the United Nations Framework Convention on Climate Change's own COP31 page. Türkiye holds the conference presidency after a hosting dispute with Australia was resolved by splitting the job: Türkiye runs the summit while Australian Climate Minister Chris Bowen serves as President of Negotiations, with the authority to appoint co-facilitators, draft text and issue the final cover decision, as the Australian government's own prime ministerial statement on the arrangement spelled out last November.

The American absence traces to a single document: Executive Order 14162, "Putting America First in International Environmental Agreements," which President Trump signed on his first day back in office and which the Federal Register's published text shows directed the U.S. ambassador to the United Nations to notify the Secretary-General of withdrawal from the Paris Agreement. Under the treaty's own terms, that notice took a year to take legal effect, lapsing on January 27, 2026. It is the second time the United States has walked out of the agreement it helped negotiate, having rejoined under President Biden after its first exit in 2020, and it has never ratified the preceding Kyoto Protocol at all.

Into that vacuum steps a 19-member congressional delegation, organized by the nonpartisan Sustainable Energy and Environment Coalition Institute, that will travel to Antalya for the full two weeks. Its organizer, Representative Sean Casten of Illinois, announced the trip a day after Democrats won sweeping midterm victories that returned them to control of the House and Senate. Casten told reporters the group would still perform an "important diplomatic function" even without a governing majority yet seated, and that its message abroad is that "America has spoken," pointing to shared pressures like climate-driven financial volatility and the cost burden of tariffs on solar panels and electric vehicles, according to Euronews' reporting on the delegation and a parallel account in the Hürriyet Daily News. State and local officials will attend separately under the America Is All In coalition, the same subnational network that filled the identical void a year earlier.

The rules get written anyway

The temptation is to treat COP31 as symbolic theater that a few dozen American officials can patch over by showing up with the right attitude. That misreads what these conferences actually do. COP29 in Baku produced a binding-in-practice goal: developed countries agreed to help mobilize at least $300 billion a year for developing nations by 2035, nested inside a broader call to scale all public and private finance to $1.3 trillion annually, a target the parties termed the "Baku to Belem Roadmap to 1.3T" from the conference's own UNFCCC page. COP31's agenda, by Türkiye's own framing, is built around turning that roadmap into implementable rules on finance, carbon markets and adaptation funding. Those rules will determine which countries' clean-energy exporters get preferential treatment, how carbon credits are verified and traded under the Paris Agreement's Article 6 mechanisms, and which capital flows qualify as climate finance versus ordinary commercial lending.

None of that is decided by acclamation from the visitors' gallery. It is negotiated line by line among parties with standing, and the United States, having surrendered its party status, has no vote, no seat on the drafting committees Bowen will empanel, and no formal claim on the outcome. A congressional delegation can lobby, listen and signal intent. It cannot object to language, block a consensus text, or insist that American firms get the same treatment the agreement extends to European or Chinese ones. The Australia-Türkiye hosting compromise itself is a preview of how fast institutional arrangements reshuffle once a major power steps back: other governments simply divided up the authority Washington once might have contested for itself.

Diplomacy without a portfolio

This is not a new experiment. At COP30 in Belem last November, roughly 100 American state and local leaders attended in the total absence of a federal delegation, under the same America Is All In banner now returning to Antalya. California Governor Gavin Newsom, the coalition's co-founder, was characteristically blunt about what that meant in practice, calling the federal no-show "the own goal of a U.S. president who simply doesn't understand" the scale of the opportunity, and declaring flatly that the United States "is nowhere to be found at COP30 today," as ThePrint reported from Belem.

"The federal government remains the single most important actor" in international climate diplomacy, Carnegie South Asia's Milan Vaishnav told reporters at the time, even as governors and mayors tried to fill the space it left behind.

Vaishnav's caution has held up. A year of subnational showmanship did not produce a seat at COP31's negotiating table; it produced a repeat performance, this time with members of Congress added to the cast. State-level agreements, like California's partnerships with Mexican and Brazilian states, can move real money and real emissions reductions. What they cannot do is bind the federal government to a finance commitment, set a national position on carbon-market rules, or reassure trading partners that American climate policy will survive the next administration change intact. That credibility problem compounds with repetition: a country that joins, leaves, rejoins and leaves again is one whose commitments other governments have learned to discount in advance, regardless of which faction of its government shows up at the airport.

What the trip buys, and what it doesn't

None of this means the congressional trip is pointless. Casten is right that Republicans have, at other moments, backed durable environmental frameworks, from acid-rain emissions trading to the Montreal Protocol's ozone protections, and a bipartisan-leaning delegation signaling that Washington's absence need not be permanent is worth more than silence. Democrats retaking both chambers after Tuesday's midterms also changes the medium-term calculus, even if a presidential veto still blocks any near-term reversal of the Paris withdrawal. Relationship-building, briefings with Bowen's negotiating team, and visible continuity with allies all have value that will outlast this particular summit.

But value at the margins is not leverage at the center. The honest accounting of COP31 is that the United States will spend two weeks as a guest at a negotiation that will set terms it did not help write, governing a market in clean technology and carbon finance that American companies will still have to compete in. A delegation of 19 members of Congress, however well-intentioned, is attending a summit the country already lost its place at. The cost of that absence will not show up this month. It will show up in 2027 and 2028, when the finance rules, carbon-accounting standards and trade-adjacent provisions settled in Antalya start determining who gets capital and who gets left paying someone else's tariff.