For now, the standoff leaves four players circling the same crisis: Iran, cast by Trump as the “probable” hand behind the pipeline attack; the Iran-aligned Houthis, advancing in Yemen while quietly working the phones to keep the US at arm’s length; Saudi Arabia, pressing its superpower ally for the firepower it has leaned on before; and the United States, backing Riyadh but refusing, at least for now, to pull the trigger. Caught in the middle is the oil market — and a world watching prices climb as the region edges closer to a wider confrontation.