Venezuela was rocked by new protests this week as opposition leader Juan Guaido declared the final phase of what he's dubbed "Operation Freedom". He's got the backing of some 50 countries around the world in his quest to take power away from President Nicolas Maduro. But the key to the power struggle lies with Venezuela's powerful army. The military has always played an important role in the political life of the country, taking part in coups that have both toppled and restored power.