Former US president Donald Trump has sharply criticised California Governor Gavin Newsom’s newly announced climate partnership with the United Kingdom, describing the arrangement as “inappropriate” and asserting that foreign policy authority rests with the federal government.

Speaking shortly after details emerged of Newsom’s agreement with UK officials — including support for expanded clean energy cooperation and significant private-sector investment commitments — Trump argued that international negotiations and formal policy alignments should be conducted by nationally elected leadership rather than individual states.

He maintained that unified federal direction is essential to preserving the strength, credibility and coherence of the United States on the global stage.

Newsom’s UK visit resulted in a memorandum of understanding focused on climate collaboration, research partnerships and the expansion of clean technology markets between California and Britain.

The agreement was accompanied by a nearly one billion dollar clean-tech investment pledge from UK-based Octopus Energy aimed at scaling operations in California.

The governor framed the deal as an example of state-level leadership advancing climate innovation and economic growth.

Trump, however, emphasised that trade policy, international agreements and diplomatic engagement fall squarely within the remit of federal constitutional authority.

He suggested that subnational initiatives risk creating confusion about national priorities and undermining coordinated economic strategy.

Supporters of Trump’s position note that the Constitution assigns the conduct of foreign relations to the executive branch, underscoring the importance of centralised leadership in negotiations affecting trade, energy and international standards.

The exchange highlights a broader policy divide between state-led climate diplomacy and federal oversight of international engagement.

While California has long pursued global environmental partnerships, Trump’s remarks reflect his consistent position that American economic and diplomatic interests must be directed through national institutions to ensure clarity, accountability and strength in dealings with foreign governments.

The debate unfolds against the backdrop of ongoing national discussions over climate policy, energy independence and the proper balance between state innovation and federal authority in shaping America’s global posture.