If he put some effort into it there are areas that he could be effective, but he rarely does. He wants to save his energy for the other side of the court. A very common theme unfortunately in today’s game. Even Kawhi Leonard who was once a dominant two-way player is no longer a great defensive player. He’s focusing on the offense by his own admission.
Harden is a horrendous perimeter defender. The Rockets were constantly hiding him on defense even when he was younger. He had an inability to track his man on cuts, particularly when forced to work around screens. And because he likes to gamble on Steals he routinely gives up drives to the basket. Gifs galore on that one all over the Internet. Not guarding a elite offensive player, Just blowing straight by him.