Because of the vagaries of both it’s constitution and legal systems,Rome was inevitably reactive in its initiatives. As Rome started to expand the Senate was aware that good quality arable land, gold, silver, precious jewels, silk, and spices all lay beyond the territory they controlled.
Initially they made use of the Greek trading colonies which had proliferated along the northern shore line of the Mediterranean. However the the Romans regarded trading as a a disreputable activity. To them an occupation which bought a commodity at one price and sold at a highly inflated price without doing anything to enhance the commodity whilst it was in their possession must be tainted with corruption. It was perhaps this attitude which enabled Rome to treat these Grecian trading partners so shamefully by imposing trade restrivtions and then invading.
Nevertheless for over two hundred years Rome came to dominate every shore of the mediterranean. the external appearance of success hid however much internal turmoil with revolution, civil war and murder being commonplace.