Development of TOPOL is suppose to be a start treaty violation. But national security is more important than treaties??
http://russianforces.org/blog/2007/07/is_rs24_a_new_missile.shtml
The problem that has been holding back the a straightforward MIRVing of Topol-M was that it would violate one of the START Treaty provisions. The START Treaty prohibits "increasing the number of warheads attributed to an ICBM or SLBM of an existing or new type" (Article V.12d). Since for the purposes of the treaty Topol-M is just a "variant" of the Topol missile, Russia cannot simply declare that from a certain point Topol-M will be equipped with multiple warheads. To make MIRVing possible, Russia has to have a new missile, with multiple warheads attributed to it from the very beginning