First, officers must understand the meaning of the right to be free from an unreasonable search and seizure guaranteed under the fourth amendment of the U.S. Constitution. Second, officers must be familiar with the definition of "objective reasonableness," which refers to what another officer would likely do if placed in the same or similar circumstance. In making this judgment, courts must consider the severity of the crime at issue, whether the suspect posed an immediate threat to the safety of officers or others, and whether the suspect was actively resisting arrest or attempting to evade arrest by flight. The best place to find the facts that support a finding of objective reasonableness is in the original use-of-force report. Case law prevents courts from using hindsight in judging an officer's actions. They can only consider whether, given the circumstances faced by the officer, his/her actions were "objectively reasonable." The primary defenses an officer can use in defending against a use-of-force lawsuit are that the use of force was reasonable and that the officer had qualified immunity. The defense of reasonable use of force involves a factual argument that, under the circumstances, the officer's actions were acceptable and reasonable. In the other defense, officers are entitled to qualified immunity if "their conduct does not violate clearly established statutory or constitutional rights of which a reasonable person would have known." This requires that courts first ask whether the facts alleged show the officer's conduct violated a constitutional right of the plaintiff. This defense must be raised in a motion at the earliest opportunity, because the defense is designed to absolve an officer from the lawsuit in its entirety.