Technically yes. But he should state his position more forcefully. As commander in chief, Trump has (had) the legal authority, in my opinion, to give Mike [traitor] Pence a direct order to reject the vote count in order to fulfill Pence's constitutional duty, and defend the USA against a legitimate threat to our election system.

Of course, such an order would have caused controversy. But, that is how the chain of command, and our elected officials sworn duty to the constitution is supposed to work.