The role of Congress and its powers

Since the heady days of FDR's New Deal in the 1930s, the federal bureaucracy has grown into a massive, complicated, expensive and politically savvy colossus. It performs, day in and day out, the myriad and mundane functions of governance in America. It is the "permanent" government and is arguably the most powerful political force in America. Given the size and complexity of the executive branch of government, how can we as citizens hold it accountable for its decisions and actions? Be specific and talk about the role of Congress and its powers