Subsequently it did fall, and he was--I will not say the conspirator, nor will I judge the question by saying that he was the traitor; but the man of power who, having the legions of the Republic in his hands, used them against the Republic.

I can well understand that he should have joined such a conspiracy as this first of Catiline, and then have backed out of it when he found he could not trust those who were joined with him.
This conspiracy failed.

One man omitted to give a signal at one time, and another at another.

The Senate was to have been slaughtered; the two Consuls, Cotta and Torquatus, murdered, and the two ex-Consuls, Sulla and Autronius, replaced.

Though all the details seem to have been known to the Consuls, Catiline was allowed to go free, nor were any steps taken for the punishment of the conspirators.
The second conspiracy was attempted in the Consulship of Cicero, B.C.
63, two years after the first.