We know frightfully little about the actual functioning of the public grain. Prior to the lex Clodia frumentaria in 58 public grain was still sold at market, but we do not know how exactly it got there. Was grain from the public storehouses sold on site, or did the aediles hand it off to people to sell at market? After 58 public grain was provided free of cost to all citizens, but similar problems arise. How exactly was all that grain made available? Was it available at particular locations, or distributed through the various vici? Was public grain made available continually, or was it only distributed at particular times on particular days? How would either of those work? We really don't know.

We do know that public grain, before and after 58, was distributed in units of 5 modii per month. So we know that there was an expectation that individual citizens were expected to be able only to collect their particular amount, and that the remaining grain required to survive was to be purchased on the private market. We also know that in the 50s there was great abuse of the system, but not by people getting "back in line." When Pompey was appointed to the cura annonae he had to excise many citizens from the roll, in an attempt in particular to combat the mass manumissions of slaves, whose masters could collect part of their freedmen's grain allowances as part of their patronal privileges. We know that some sort of roll was probably made by Pompey, and we're certain that one was drawn up by Caesar, limiting the number of eligible recipients to only 150,000, but updating the roll regularly to make up for citizens who had died or were otherwise no longer in the urban population. Under Augustus the public grain was distributed from known positions and those eligible to receive it--a relatively small minority--were known by their possession of tesserae, tokens that, while not eliminating the possibility of fraud, surely made it harder.

The problem is that we really don't have very much information as to how this worked after Clodius passed his lex frumentaria. Cicero in the de domo sua makes reference to Clodius' supposed empowerment of Sex. Cloelius, claiming that he even handed over to Cloelius the keys to the granaries and power in the provinces. Cicero's attack here must be purely rhetorical, as there is no evidence that the cura annonae existed at all as a regular office before Pompey. Whatever the arrangement under Clodius, it apparently didn't look like what came later. The problem is compounded by the fact that even the regular checks on citizen enrollment, most importantly the census rolls, would not have worked for the purpose. In the first place, if grain distributions were made at multiple locations--as they must have, in order to supply so massive a population (some 300,000 under Pompey, down from a larger number in 58)--this would not have helped any. More importantly, the census had not been conducted in over a decade in 58, whereas we know that these newly manumitted slaves were able to claim their 5 monthly modii. Tatum thinks that Caesar distributed the public grain through the owners of insulae, from a reference in Suetonius to Caesar's use of these owners to provide a headcount of the city for the purposes of the cura annonae--the sources do not in fact say that, and Tatum is interpreting a connection there. Tatum thinks that collegia distributed the public grain, but such munera would be unprecedented for collegia before and after, and there is no evidence whatsoever in the sources, except the convenience that the enrollment of the collegia would have provided. Not great logic. It's just as likely that the grain was distributed at set locations, although extremely importantly we do not even know who distributed the grain before Pompey. The aediles seem to make sense, and had staff and public slaves on the books to take care of similar duties, but we're not told that. But Asconius's excerpts of the pro Cornelio mention the urban praetor Caecilius as having publici frumenti curam, "oversight over the public grain." An attack on the urban praetor later in the year by an urban mob during a food crisis would suggest that the urban praetor was placed in charge of the food supply by the lex frumentaria, but we really don't know.

If there's anything that I think Tatum is right about in this whole question, its his statement that Clodius was "loath to reject any applicant" to the public grain, even if I do not think that his reasoning really makes sense. There appears to have been little attempt to regulate the public grain at all before Pompey, and it's not hard to see why. Clodius' public support rested first and foremost on the lex frumentaria, a law so massively popular that Cicero was entirely unable to direct any rhetoric against it at all, preferring instead to attack it indirectly through Cloelius. It was hardly in Clodius' interests, even if he had thought that far, to establish clear restraints on the distributions. As soon as control passed out of the purview of the lex frumentaria Pompey, Caesar, and then eventually Augustus grasped for mechanisms to regulate the supply and distribution of grain, only at which point we begin to hear information about the logistics of supply.