The counterfactual decision to defend Atlantic reinforcements

The Royal Navy had responded to the Sverdlov cruisers by building carriers and Buccaneer strike aircraft. In the counterfactual, Britain gives protection of sea communications a stronger place alongside its commitment to the European front. American and Canadian reinforcements, equipment and supplies must be able to cross the North Atlantic. This assumes a war that continues long enough for reinforcement and resupply to matter. Submarines contribute to that protection, but they can miss a target or be required elsewhere. Carrier strike aircraft provide an additional response when the submarine force cannot meet every threat.