Stardate 20011213.1731 (On Screen): President Bush has formally announced that the US will withdraw from the ABM treaty. I think it's a mistake, but that's as may be. Legally the US can do this because the treaty itself contains a clause permitting either party to do so with 6 months notice, which is what Bush is invoking.
Though the US can do this, I'm not so sure that Bush can do so without approval of the Senate. I don't know enough about the law here, but given that the treaty was originally approved by the Senate, I bet that the Senate has to approve its termination. (discuss)