I think the problem is not down to one person - it seems like it is a group-think - problem within the security establishment, which seemed reasonable at first, but it is now very apparent that it was wrong.

I’ve now updated the post with the full article

To those who downvote based on the title alone: I know you are still in election mode, and might assume this is some pro-Trump article., but it is not. A proper stock take of the response to the Russian invasion is very necessary

I do understand those arguments, and the US has been a true ally to Ukraine - much more than the Europeans who generally didn’t spend as much as they should have, and sometimes added additional layers of caution (Olaf Scholz in particular).

But if you take a “don’t criticize us” attitude, you won’t be open to any lessons that might be learned. The lesson I hope the West, Europe in particular, would learn is that timidity and weakness invites aggression from someone like Putin.

Yes, it does add up to a lot, but it always came in just enough to keep Russia at bay. Also the permissions around where and how which weapons could be used.
When Russia invaded, Putin had no idea how corrupt, weak and inefficient his forces were.
This trickle allowed Russia enough time to turn around much of that, getting us to the point where they are now severely threatening Ukraine. If the military aid was more decisive, Russia could have been defeated early on, and the total spend could have been less than where it is now.