If you ask New Jersey Gov. Phil Murphy why Covid-19 vaccinations are happening so slowly, he’ll say the answer is simple.

“The constraint is 100 percent right now supply from the feds,” Murphy, a Democrat, told a local TV station Thursday.

Ask the feds, and they’ll say they’ve distributed far more doses than the states have used, leaving vaccines on the shelf.

“Some states’ heavy-handed micromanagement of this process has stood in the way of vaccines reaching a broader swath of the vulnerable population more quickly,” Alex Azar, the U.S. secretary of health and human services, said at a Tuesday briefing, without singling out particular states.

And if you ask the vaccine makers, they’ll say the problem is not on their side, either.

“I don’t think that we have an issue of offering less vaccines than the countries frankly need. We have much more than they can use right now,” Pfizer CEO Albert Bourla told CNBC Tuesday.

One month into a vaccine rollout that has fallen short of everyone’s expectations, the blame-shifting over who’s at fault for the bottlenecks is multiplying and threatening to disrupt vaccinations even further. And that is frustrating public health experts who say that the Trump administration’s coronavirus vaccination team seems to be sleep-walking through its final days.