We've got a "deterrent" but one which may not in fact deter. In a proliferated environment, deterrence begins to fail. That is why our enemies have in fact been abetting proliferation (E.g., Russia, China, North Korea, and France) with their various proxies, surrogates, such as North Korea...and terrorists...these need to be thwarted with a good defense as well, so that we then have the luxury of sorting out who actually attempted...repeat...attempted to attack us.
Along those lines, you can bet that the NSA, CIA liberals notwithstanding despite their incessant contrary and foolish leaks, concluded that Saddam DID have a hand in 9-11. His posing next to the painting celebrating 9-11 is no accident. We went to great expense and lengths to make things "right" afterwards.
If a nuclear hit on us is successful however, we may not have any way of ascertaining who is responsible. We need defense too.
"Agreed we need a deterrent, and should not be dismantling the MX's. Instead we should be deploying them in mobile fashion, ala the new Topol-M."
We already have an offensive deterrent. We have a very large fleet of ballistic missile submarines that circle the globe under the high seas and are virtually impossible for any country on earth to neutralize. This sub fleet can strike anywhere in the world at a moment's notice. The greatest deterrent of all, though, is the will to use this firepower when required. If some Democrat ever gets elected president again, all the high technology we possess won't protect us.
Would a Democrat ever believe that the proper response to a nuclear missile attack on California from North Korea would be a nuclear retaliatory strike? I don't think so! We've already seen that these people don't have the will to avenge the deaths of over 3000 of their own constituents in their own congressional districts! They'd be more likely to just chalk up the loss of Los Angeles as a regrettable, lamentable, but ultimately forgettable, experience. Don't you think?