Procedural defenses are legal arguments that challenge the validity of the prosecution's case based on flaws in the legal process rather than the facts of the case itself. These defenses can include issues like improper evidence collection, lack of jurisdiction, or violations of a defendant's rights during arrest or trial. By highlighting errors or illegal actions taken by law enforcement or the courts, procedural defenses aim to show that the defendant should not be held accountable for the alleged crime due to these legal missteps.