If the senate flips he loses all power. Similar to Schumer now, who can’t do jack shyt. Problem is, unless the senator is absolutely toxic (Arizona this year) the senate race usually goes right along party lines. Biden can lose Arizona and they can still win that senate seat because McSally is so toxic Trump won’t even endorse her. Most states aren’t like that. Whoever wins the state wins the senate seat usually, and there’s just not enough wins there this cycle to flip it completely imo. Maybe he can snag a nice upset somewhere