In a later letter he discusses the details of his campaign as follows:
"The state of things in regard to my candidature, in which I know that you are supremely interested, is this, as far as can be as yet conjectured. The only person actually canvassing is P. Sulpicius Galba. He meets with a good old-fashioned refusal without reserve or disguise. In the general opinion this premature canvass of his is not unfavorable to my interests; for the voters generally give as a reason for their refusal that they are under obligations to me. So I hope my prospects are to a certain degree improved by the report getting about that my friends are found to be numerous. My intention was to begin my own canvass just at the very time that Cincius tells me that your servant starts with this letter, namely, in the campus at the time of the tribunician election, on the 17th of July. My fellow candidates, to mention only those who seem certain, are Galba and Antonius, and Q. Cornificius. At this I imagine you smiling or sighing. Well, to make you positively smite your forehead, there are people who actually think that Cæsonius will stand. I do not think Aquitius will, for he openly disclaims it and has alleged as an excuse his health and his leading position at the bar. Catiline will certainly be a candidate, if you can imagine a jury finding that the sun does not shine at noon. As for Aufidius and Policanus, I do not think you will expect to hear from me about them. Of the candidates for this year's election, Cæsar is considered certain. Thermus is looked upon as the rival of Silanus. These latter are so weak both in friends and reputation that it seems possible to me to bring in Curius over both. But no one else seems to think so. What seems most to my interests is that Thermus should get in with Cæsar. For there is none of those at present canvassing who, if left over to my year, seems likely to be a stronger candidate, from the fact that he is commissioner of the via Flaminia, and when that has been finished I shall be greatly relieved to have seen him elected consul this election. Such in outline is the position of affairs in regard to candidates up to date. For myself I shall take the greatest pains to carry out all the duties of a candidate, and perhaps, as Gaul seems to have a considerable voting power, as soon as business at Rome has come to a standstill I shall obtain a libera legatio and make an excursion in the course of September to visit Piso, but so as not to be back later than January. When I have ascertained the feelings of the nobility, I shall let you know. You must undertake to secure for me the support of our friend Pompey, since you are nearer to him than I. Tell him I shall not be annoyed if he does not come to my election."
The year of Cicero's consulship (64 B.C.) was disturbed by the famous conspiracy of Lucius Sergius Catiline. It was in this conspiracy, and during this consulship, that the culmination was reached of the discontent and plotting which had been fermenting at Rome for a number of years among a large class of the Roman nobility. The most discontented men in any community are generally to be found among those who, while belonging by birth to the upper classes of society, and accustomed to and desirous of the luxuries of life, have lost their fortunes and are unable to live in the style to which they consider themselves as of right entitled. Rome, at this time, was filled with this class of malcontents, the extravagant and wasteful style of living, combined with the reckless gambling of the age, having reduced great numbers among the young nobles almost to beggary.
The overthrow of Sulla's system of government, resulting from the defection of Pompey and the consequential loss of power and prestige by the Senate, had also roused a bitter feeling of resentment among the whole aristocratic party. The effect of this resentment upon the more solid and substantial element of this party had been to lead them to make preparations for the overthrow of Pompey upon his return to Rome; while the effect upon the ruined young nobles was to render them more than ever ready for any desperate undertaking by which they stood a chance of repairing their fortunes.
No cause, whether good or bad, ever lacks a leader; and the leader at this time was found in Catiline, a young noble of the most profligate character, but of some degree of ability and possessed of boundless audacity and ambition.
Catiline was descended from one of the oldest families in Rome, and his loyalty to the cause of the aristocracy was proved by the ferocity with which he had served under Sulla and had assisted in carrying into execution his most bloodthirsty orders. Catiline did not fail to derive some profit from these terrible times, as he secured the proscription and murder of his brother and the grant to himself of his brother's forfeited estate.
In spite of these and many other equally heinous crimes, Catiline had been elected prætor in 68 B.C. and had then spent two years in the government of Africa. Returning to Rome in 66 B.C., he at once offered himself as a candidate for the consulship. His political hopes on this occasion, however, were wrecked by an accusation of misconduct in the government of his province, brought against him by Publius Clodius. In revenge, Catiline then conspired with Autronius Pætus, who had just been deprived of the consulship for bribery, and other profligate and reckless nobles, to murder Cotta and Manilius, the successful candidates for consul, and to seize the government. According to rumor, both Crassus and Cæsar were connected with the conspiracy. The conspiracy was discovered and the enterprise was abandoned; but the proceedings against the suspected conspirators were stopped by the interposition of one of the tribunes, and the facts of the matter were never definitely ascertained.
It is a peculiar fact that Cicero was ready, at this time, to defend Catiline against the charges of Clodius; which charges, however, were dropped, without being brought to trial. Two years later, Catiline was again a candidate for consul, but was defeated by Cicero and Antonius. Catiline now began to make preparations for civil war. The plot was betrayed by a woman. Curius, one of Catiline's adherents, boasted of the plot to his mistress Fulvia, and she not only gave information of the plot to Cicero but entered into his employ as a spy upon the conspirators.
In spite of the overwhelming character of the evidence against him, Catiline continued on his course with the utmost assurance and insolence. He even took his place in the Senate, and upon being attacked by Cicero replied, "There are two parties in the commonwealth; the nobles, weak in both head and body; the people, strong in body, but headless. I intend to supply this body with a head."
On the seventh of November Catiline attempted the assassination of Cicero by two of his adherents, C. Cornelius and L. Vargunteius. Cicero was immediately informed of this attempt by his spies, and the attempt was blocked. The following day Cicero summoned a meeting of the Senate, and upon Catiline appearing in his place, Cicero burst out in the first of those famous orations against Catiline, so well known to all Latin students, which begins: "How long, O Catiline, will you thus abuse our patience? To what end will your unrestrained audacity display itself?"