Via Michael Crowley at TNR, it seems that the Obama administration has zeroed out funding for a nuclear warhead replacement program that his own Secretary of Defense considered vital to the future of nuclear stewardship. He's also proposed significant increases in funding for non-proliferation programs, and he wants to strengthen the hand of the Energy Department to put them into place.
By zeroing out the Reliable Replacement Warhead program, Obama has decided that there is no compelling reason to build the next generation of nuclear weapons. He's talked about a future where the world existed without nuclear weapons, so this isn't a surprise, although he has departed from his national security campaign platform elsewhere.
The bombs we have now - -- the non-active ones in the physical custody of the Department of Energy -- are old, require regular refurbishments to maintain their integrity, and might not reach their advertise yield rates if they were used. Am RRW program, if successful, would have meant less maintenance and more reliability -- and the assembling and distribution of at least hundreds of new nuclear weapons.
Before you conclude that Obama is a peacenik, it's important to note that the RRW's efficacy has never been clear, and leading nuclear policy experts have cautioned that changing surety requires and weapons designs could well inject as much uncertainty into the physics of the bomb as there exists today with the older, Trident W-76 nukes.
The politics of arms control are complicated, but generally, if you're on the less-nukes-in-the-world side of things, you've favored the status quo; if you're elsewhere on the issue, you probably had no objection to the RRW program.