What definition of ‘sustainable’ could he possibly mean? A higher but arbitrary share of GDP, that the country can’t afford, vs. the insane spending of the US on its overpowered but ultimately futile military (while its citizens go without basic healthcare etc.) is not sustainable. — ‘On Sunday night, Matt Whitaker, the US ambassador to Nato, said certain Nato members were not moving fast enough: “Some allies are doing more than others. Poland, the Nordic countries, the Baltic countries lead the way. “But many others are lagging behind, and President Trump expects all allies to step up immediately and not only get on a sustainable path to the 5% but to get to 5% as soon as possible.”’ https://www.theguardian.com/politics/2026/jul/06/keir-starmer-nato-summit-us-rebuke-defence-spending