Congress can't do much of anything. Their ability to pass anything more important than naming a post office is essentially nil. They can't even perform the basic operation of keeping the government open, except by heroic last-minute effort.

Congress' rules were designed to protect minority opinions, and they're easily taken advantage of to prevent anything from happening at all. A fair number of Congresspeople were elected with the specific goal of locking Congress up, and they're pretty effective at it.