They didn't. At the time that Jesus lived the Romans had very little dealings with him. In fact they didn't even know who he was. That's why when it came time to arrest Jesus they had to have someone (Judas) point him out. It was only a certain group of Jewish authorities who perceived Jesus as a threat and so acted against him.
The way that the Enlightenment's theories of government viewed the role of government was that government was meant to serve the people, not the other way around.
