This paper offers a comprehensive study of the jurisprudence on the ‘as a result of unforeseen developments’ test under the WTO's safeguards (SG) rules. It contributes to the existing scholarship by making three fresh arguments. First, the Appellate Body's decision to ‘revive’ this test as a prerequisite for the application of SG measures is not necessarily incompatible with the drafting record of the SG Agreement, even though this agreement does not make explicit reference to the test. Second, the test is not excessively difficult to satisfy under the standard of review established by case law, even though governments failed to pass it in almost all SG disputes to date. Third, in sharp contrast, the recent US–Safeguard Measure on PV Products decision took a strikingly more deferential approach which fell far short of the established standard of review, leading to the first and only decision in which the test was found to be satisfied. This decision has arguably created a new standard which could lead to abuse of SG measures and damage to the dispute settlement system and hence should be avoided in future disputes.