Ivan Eland: Despite all the hoopla about President Barack Obama’s summit on nuclear security and a new arms control deal, the eventual results of his laudable efforts will probably be modest and will likely be dwarfed by the damage to nuclear security done by George W. Bush’s prior administration. . . . but at least Obama has refocused world attention on what is still the only existential threat in U.S. history—nuclear war—and the improbable, but potentially disastrous, threat of nuclear terrorism. In its pursuit of nation-building and military social work in overseas quagmires, the Bush administration had neglected both.