The normally genteel world of international space policy turned ugly this week as several prominent US space companies—including SpaceX, Blue Origin, Stoke Space, K2, and Starcloud—pulled out of a high-profile French space summit organized by the country’s president, Emmanuel Macron.

Politico first reported the diplomatic turmoil, saying that the White House “pressured” US space companies to skip Macron’s space summit in Paris next week. Since then, the companies have largely pulled out of the meeting without commenting publicly, though some US representation remains on the two-day program.

Much of the tension stemmed from an official with the White House Office of Science and Technology Policy, or OSTP, who led a call with US space companies late last week. The call was convened in response to queries from US industry about the French meeting, which is not part of the traditional circuit of international space conferences.

According to sources, the White House officials were concerned that the summit might include some policy prescriptions around contentious issues such as sharing of spectrum, which could potentially be detrimental to US companies. The officials advised the companies that attending might not be in their best interests, suggesting that they might be pressured to endorse policy positions that misrepresent their preferences.

This diplomatic fallout raises questions about the future of international collaboration in space and the extent to which political interests may steer scientific and technological progress.