Just a quick note on the name: provocatio is a latin term dating from around the 5th century B.C. Rome, at the time, was ruled by an aristocracy known as the patricians. These were the people who could trace their ancestries back to the founding of Rome in 753B.C. Initially, the Roman Senate was mad up of patricians. Initially, all the office-holders (magistrates) were patricians.
There was another group of people living in Rome at the time, and they were known as plebians. (It is believed that there was a third group neither patrician nor plebian. There is little historical trace of them, however.)
The plebians often felt that they weren't getting a great deal of benefit from their citizenship of Rome and the work they put into advancing her cause. For example, they weren't allowed to hold any of the administrative offices: consul, praetor, etc. After a few "secessions" – general strikes, really – they began to gather more rights unto themselves.
One of these was provocatio. If a plebian believed that his rights, entitlements chattels or property were being abused by a magistrate, he could invoke provocatio. This would result in one of the elected plebian representatives, a tribune, acting on the "victim's" behalf. Quite often, this would result in the tribune excercising his veto (yes, that's where the word comes from – it means "I deny"). Once used, the magistrate you have to abide by the veto (and stop his harrassing action) or run the risk of having the tribune bring down the wrath of all the plebians onto himself.
In practice this worked well until the first 100 years or so B.C. when things began to go a bit haywire. Tribunes held the office for one year, and typically didn't go for it a second time. The tribune's person was sacrosanct. That meant that even if the magistrate was a dictator, who had power of execution over all roman citizens, to hurt or even impede the tribune would have caused the plebians to respond as a group, something they swore to do when they elected the tribunes.
I have named this blog provocatio because I would like to use it from time to time to challenge the accepted beliefs people have of the world about them. Quite often, those whose outlooks need challenging are in positions of authority. Taking the electronic voting issue for example, how many times did Martin Cullen say that the objections were from uninformed luddites?