If the GOP loses the Senate majority in this upcoming election, will they still have enough power to block Supreme Court Justice nominee?
If the GOP lose the Senate this election, will they still have enough power to block Supreme Court Justice nominations?
No. With a Senate majority, the Democrats can change the rules to allow a simple majority to carry a cloture vote and end a filibuster. And they have said that if Republicans filibuster a candidate for what they consider to be insufficient justification, that they will.
How is their refusal to "advise and consent" legal?
If they could not refuse their consent, what is the point of requiring their advice and consent? They have no requirement to give consent. The President is required to get it.