It was at this critical moment that Gilpatric stepped in to settle the argument. "Essentially, Mr. President," Gilpatric was recorded telling Kennedy, "this is a choice between limited action and unlimited action, and most of us think it is better to start with limited action." It was Gilpatric's intervention that changed the direction of the discussion, according to Harvard professor and former Department of Defense official Graham T. Allison, who authored a book, "Essence of Decision", about the crisis. Proposing the blockade was McNamara and Gilpatric's solution to providing President Kennedy with a strong response – but short of the airstrike that McGeorge Bundy and others were pushing. By crafting their solution, and with the normally reticent Gilpatric speaking up forcefully for it, the two managed to change the thrust of policy. The President followed Gilpatric and McNamara's recommendation.