No one person in our government is in complete control. It is easy for a person to point a finger at one person, a figure head, like Barrack Obama and lay blame, however issues are never that crisp and clear. The United States government, all branches really, has turned into a unworkable mess as it sits, so you can't blame one part without blaming the others.
Congress is responsible for gridlock in the nation's capital. If Congress feels the president is ineffectual, they can try to override his vetoes. The problem is the Senate is controlled by Democrats while the House is controlled by Republicans. Blame doesn't lie squarely on Congress--voters are the ones who put those people in places of power in the first place. If there are problems with gridlock, the voters are to blame and not Congress in this republic form of government.