Final answer:
The claim that a state legislature has overridden a governor's veto in every session since 1977 cannot be universally affirmed as it varies by state. Overriding a veto is challenging and requires a supermajority, which does not happen in every legislative session.
Step-by-step explanation:
The statement that the state legislature has successfully overridden a governor's veto at least once in every legislative session since 1977 is too broad and lacks specificity to be universally accurate; it may vary from state to state. In many states, overriding a governor's veto is a challenging task, as it requires a supermajority vote in the legislature, which often means that members of the governor's own party must vote against the governor. When it comes to the abilities of the governor and interactions with the legislature, all governors have the power to veto bills, including line-item vetoes in appropriation bills, but the process to override such a veto is state-specific and not guaranteed to occur every session.