If the US were willing to compromise some of it's core values, then we could probably stop AI development domestically.
But what about the rest of the world? If China or India want to reap the benefits of enhanced AI capability, how could we stop them? We can hit them with sanctions and other severe measures, but that hasn't stopped Russia in Ukraine -- plus the prospect of world-leading AI capability has a lot more economic value than what Ukraine can offer.
So if we can't stop the world from developing these things, why hamstring ourselves and let our competitors have all of the benefits?