with nuclear warheads as their main weapon of attack, this idea involves the release of biological or chemical sub-munition weapons/agents from the missile shortly after the boost phase of the attacking ICBM. Because missile defense systems are designed with intent to destroy main attacking missiles or ICBMs, this system of sub-munition attack is too numerous for the system to defend against while also distributing the chemical or biological agent across a large area of attack. There is currently no proposed countermeasure to this type of attack except through diplomacy and the effective banning of biological weaponry and chemical agents within war. However, this does not guarantee that this countermeasure to missile defense system will not be abused via extremists/terrorists. An example of this severe threat can be further seen in North Korea's testing of anthrax tipped ICBMs in 2017. Dynamic trajectories Countries including Iran and North Korea may have sought missiles that can maneuver and vary their trajectories in order to evade missile defense systems. In March 2022, when Russia used a hypersonic missile against Ukraine, Joe Biden characterized the weapon as "almost impossible to stop". Boost-glide hypersonic weapons shift trajectory to evade current missile-defense systems. Glide Phase Interceptor (GPI) will provide defense against maneuvering hypersonic weapons. Multiple independently targetable re-entry vehicles Another way to counter an ABM system is to attach multiple warheads that break apart upon reentry. If the ABM is able to counter one or two of the warheads via detonation or collision the others would slip through radar either because of limitations on ABM firing speeds or because of radar blackout caused by plasma interference. The first MRV was the Polaris A-3 which had three warheads and was launched from a submarine. Before regulations on how many warheads could be stored in a MIRV, the Soviets had up to twenty to thirty attached to ICBMs. Jammers Jammers use radar noise to saturate the incoming signals to the point there the radar cannot discern meaningful data about a target's location with meaningless noise. They can also imitate the signal of a missile to create a fake target. They are usually spread over planned missile paths to enemy territory to give the missile a clear path to their target. Because these jammers take relatively little electricity and hardware to operate, they are usually small, self-contained, and easily dispersible. Command and Control Command and control, battle management, and communications