But none of that seemed to matter, at least at first. The official explanation for the decision didn’t pass muster, as the F.D.A. commissioner, Marty Makary, was perhaps acknowledging when he suggested, in response to a public backlash, that the F.D.A. might eventually approve the vaccine — and then confirmed, today, when news broke that the agency would in fact proceed with a normal review. The original judgment had been such a departure from protocol that it seemed to threaten the whole pipeline of future vaccine development, by destabilizing the regulatory framework that drugmakers rely on. Even after the reversal, it was hard to know how much any company should trust an F.D.A. ruling, and indeed many had already announced they would be pulling back on vaccine research. What could have possibly been the motivation? Perhaps a style of retributive policy-making animated by pandemic spite — a desire to play favorites and punish enemies according to longstanding grievances rather than even to pretend to consider the science itself.