Power is expressed by those who wield it.
With only a two party congress (we need more Joe Liebermans) and the overwhelmingly priority of those elected is to get RE-elected, congress spites itself while the president of the time runs the country based on their own agenda. I believe since Reagan, congress has been whittled down to a side show for the public to focus on while the other two branches of government dictate for good or bad the direction of our country. Prior to Reagan, there were great Presidents going back to Franklin Roosevelt. Unfortunately due to wars, conflicts, assassination, controversy, impassivity and possible weakness, congress had to step up to the plate a earn their keep and run the country. When Reagan was elected it was about him, which at that time in history, our country probably needed. Since then our government has been president-centric. George Washington tried to tell congress that the United States should never, ever, be about the president and that congress should be the voice of the people. The peoples voice is often ignored, denied, or only taken into consideration by the latest vocal minority of the minute.
Congress as a whole has power but denies itself that power by not working together as a cohesive entity in the trust of the people of the country.