Wheeler's promptings were influenced by the severe strain imposed upon the U.S. military by the Vietnam commitment, one which had been undertaken without the mobilization of its reserve forces. The Joint Chiefs had repeatedly requested national mobilization, not only to prepare for a possible intensification of the war, but also to ensure that the nation's strategic reserve did not become depleted. By obliquely ordering Westmoreland to demand more forces, Wheeler was attempting to solve two pressing problems. In comparison with MACV's previous communications, which had been full of confidence, optimism, and resolve, Westmoreland's 12 February request for 10,500 troops was much more urgent: "which I desperately need ... time is of the essence". On 13 February, 10,500 previously authorized U.S. airborne troops and marines were dispatched to South Vietnam. The Joint Chiefs then played their hand, advising President Johnson to turn down MACV's requested division-sized reinforcement unless he called up some 1,234,001 marine and army reservists.