Running for the consulship for a second time after having lost the first time, Catiline was an advocate for the poor, calling for the cancellation of debts and land redistribution. However, there was substantial evidence Catiline had bribed numerous senators to vote for him and engaged in other unethical conduct related to the election. Cicero, in indignation, issued a law prohibiting such machinations. It seemed obvious to all that the law was directed specifically at Catiline. Catiline, in turn, conspired to murder Cicero and the key men of the Senate on the day of the election in what became known as the Second Catilinarian conspiracy. Cicero discovered the plan and postponed the election to give the Senate time to discuss the attempted coup d'état.
You can listen to them, in Latin, here