Vice President Al Gore today signed an agreement with Russia to irreversibly transform excess nuclear weapon plutonium into non-weapons grade plutonium, Gore's office announced. President Clinton and Russian President Vladimir Putin originally announced the plan in Moscow June 4. Now that it has been signed by Gore and Russian Prime Minister Mikhail Kasyanov, the agreement will enter into force today, an announcement stated. The agreement "advances the critical task of reducing stockpiles of excess weapons plutonium and contributes to key...