Vanquished Vaccines and Vetocracies

There were various approaches to fighting COVID, and in retrospect we ended up with the worst of all. It's understandable that we didn't follow China in taking the authoritarian approach. And it's also understandable that we weren't going to be as lackadaisical as we were in 1918. But what kept us from taking the technolibertarian approach of human challenge trials, first doses first, and approving the Astrazeneca vaccine as soon as Europe did. And more importantly why are we now taking the exact opposite approach, "pausing" Johnson and Johnson, while Europe restricts Astrazeneca? Why are we so bold when it comes to government spending and so timid when it comes to vaccine safety?