"And Russia has expressly reserved the right to walk away from the treaty if it believes that the United States has significantly increased its missile defense capability."
This is true, but, as is the case with all treaties, Russia and the United States expressly reserve the right to withdraw for any reason if they believe it endangers their "supreme interests." President George W. Bush withdrew from the 1972 Anti-Ballistic Treaty under such a clause. Any president, Russian or American, can pull out of this treaty, too, with three months' notice. (See Article XIV, Section 3.)
However, the Russians would have to consider the following: If they did withdraw from the treaty, that would probably aggravate tensions to the point where the United States would probably accelerate missile-defense deployments and perhaps resume an offensive arms buildup, too—a resumption that we can afford a lot more than they can.
"The treaty empowers a Bilateral Consultative Commission with broad latitude to amend the treaty with specific reference to missile defense."
This is silly. Previous arms treaties—negotiated by Democrats and Republicans—have created similar commissions. This one, like the others, has no "broad latitude to amend the treaty." In fact, Article XV of New START states explicitly that the commission can make no changes that affect "substantive rights and obligations." Its purpose, as noted in several other sections (Articles V and XIII of the treaty, Part VI of its protocol), is to "resolve any ambiguities that may arise" over the 10 years that it remains in effect. These articles contain no "specific reference to missile defense," by the way.
"The treaty also gives far more to the Russians than to the United States. As drafted, it lets Russia escape the limit on its number of strategic nuclear warheads."
Again, there might have been some static on the phone line. The treaty does let Russia get by without cutting any of its strategic "delivery vehicles" (missiles and bombers). Each side is limited to 700, but Russia right now has only 600; the United States has 850, so it will have to cut back a little. However, both sides will have to reduce their warheads—the actual nuclear weapons—to 1,550. And, for what it's worth, Russia, which now has 2,787 warheads, will have to cut back more than the United States, which now has 2,252.
"For example, rail-based ICBMs and launchers are not mentioned."
First, neither Russia nor the United States has any rail-based ICBMs or launchers. Second, the treaty does deal with mobile ICBMs, in two ways. Article IV, Section 1 states that ICBMs can be deployed "only at ICBM bases." If, in some perverse wordplay, the Russians claim that a railroad line is a "base," Article III, Section 5b notes that an ICBM is counted under the treaty's limits the moment it leaves the production facility (which other sections of the treaty place under constant monitoring); it doesn't matter where the missile goes afterward, it's still counted as an ICBM. So while mobile missiles might not be "mentioned" by the treaty, they are, in effect, restricted.
"Similarly, multiple nuclear warheads that are mounted on bombers are effectively not counted. Unlike past treaty restrictions, ICBMs are not prohibited from bombers. This means that Russia is free to mount a nearly unlimited number of ICBMs on bombers—including MIRVs (multiple independently targetable reentry vehicles) or multiple warheads—without tripping the treaty's limits."
This is where I began to wonder if Romney had fallen prey to someone, perhaps a spy from Sarah Palin's camp, who wanted to make him look like an idiot.
ICBMs are not "mounted on," or loaded inside, bombers. The only nuclear weapons carried by bombers are bombs; that's why they're called bombers. (Many years ago, some B-52s and B-1s were equipped with air-launched cruise missiles, which flew through the atmosphere, as opposed to intercontinental ballistic missiles, which arc outside the atmosphere. These ALCMs are almost completely phased out, in any case.) Certainly bombers are incapable of carrying MIRVs (which, by the way, are "multiple warheads" loaded onto the tips of missiles).
I think Romney's ghostwriter might have mixed up one of his talking points. New START counts each bomber as if it is carrying just one nuclear bomb, even though it almost certainly carries several. This counting rule was established for practical reasons. A bomber might carry three bombs one day, a dozen the next, with no need to alter its design. There's no way to verify how many it's carrying. So they agreed just to count one bomber as one bomb.