The Senate was the predominant political institution in the Roman Republic. The Senate's authority derived primarily from custom and tradition. It was also one of the few places in which free political discussion could take place. The Senate's principal role was as an advisory council to the consuls on matters of foreign and military policy, and it exercised a great deal of influence over consular decision-making. The Senate resolved disputes between magistrates and oversaw the allocation of public resources to magistrates. It also assigned magistrates to provinces. Some of its responsibilities were enshrined in specific legislation, such as the "lex Caecilia Didia" which gave the Senate power to declare a law invalid.