The most obvious use of philosophy within Cicero’s speeches is as a source of invective: Stoicism against Cato in the Pro Murena, Epicureanism in In Pisonem. However, even here Cicero is careful to show that philosophical adherence itself is not a fault; but only faulty adherence. Elsewhere in the speeches, Cicero draws on Stoic theories of society in constructing his views of the relationship between the res publica, crisis, and tyranny and in articulating the justification for tyrant killing: this line of argument can be traced from the Catilinarians through Pro Milone down to the Philippics.