As a candidate, Barack Obama declared war on nukes, but now he's calling a tactical truce. To encourage tougher international action against proliferation, he hopes to ratify the 1996 Comprehensive Nuclear-Test-Ban Treaty. The idea of outlawing weapons tests was so divisive that the Senate said no in 1999, and Republicans are ready to fight if Obama tries again. To buy them off, Obama will propose updating America's aging nuclear-weapons manufacturing complex and funding design work that would tiptoe to the very edge of crafting a new warhead, according to a senior official's recent briefing to a small group of outside experts. (Candidate Obama pledged "not to authorize the development of new nuclear weapons and related facilities.") Meanwhile, the Pentagon, working on a new "nuclear posture review," is contemplating a force of 1,000 weapons deployed and 2,000 in reserve. That's well below the 1,675 agreed to in Moscow this May, with 2,500 currently in reserve, but it dismays some of those who have been briefed. "It's Bush Lite," says one, speaking anonymously to preserve his access. "That's not what Obama promised."