Airstrikes by the UK and the US are doubtless degrading the ability of Iran-backed Houthi militants to attack shipping in the Red Sea but there is little sign the action is deterring them.
Royal Air Force warplanes linked up with the US military for a third time to hit "multiple military targets" on Saturday night in an operation that was also supported by a number of other allies, including Canada, Denmark and the Netherlands.
Grant Shapps, the defence secretary, said the strikes were "proportionate and targeted" and insisted that the action was "not an escalation".
Yet just saying these words does not make it so, in the same way as attempts by the UK to distinguish its action in Yemen from Israel's war in Gaza, even though the Houthis only started targeting international shipping along their coastline in protest at the conflict.
London and Washington first launched joint airstrikes against the Houthis on 11 January after the militants ignored repeated warnings to stop launching drone and missile attacks against ships passing through the Red Sea and the Gulf of Aden.
The stated aim of the operation - which targeted drone and missile launch sites, radars and other facilities used by the rebels to strike at ships - was to deter future attacks.
Yet, since that date the Houthis have continued to pose a menace to vessels.
As a result, the US military, which has a powerful aircraft carrier in the region and missile-launching ships, has launched multiple strikes against Houthi targets - the majority of them unilaterally.
The UK has now joined in with these strikes for a third time and yet there is little evidence that the action is removing the threat, given that the Houthis have vowed to keep up their operations until Israel ends its war in Gaza - triggered in the wake of the 7 October terrorist attack against Israel, by another Iran-backed group, Hamas.