It might sound like a simple question, but as usual it is much more complicated than that.
According to the US Constitution, it is "We the People". It's right there in the preamble so it must be true. Right? We should be in charge but in practice we are a representative democracy (not a direct democracy). What this means is that we elect government officials (US House and Senate) to represent us and pass and enforce laws for the land.
A direct democracy was tried in ancient Greece but it broke down as the population grew and diverse interests began to surface. In a direct democracy, every person (or eligible person in the case of Greece) had a vote and could advance any topic or issue they desired. You can imagine how this works in a group of 10. Can you imagine it in the case of 350 million? The closest direct democracy system we have today is the State of California. In California the state allows for public referrendums to be added to the ballot during each election. This is why California has different pollutions laws for cars that are stricter than any other state. All of these referrendums have led to legistlative red tape that in no small part has contributed to California struggling financially.
Direct democracy doesn't work in practice even if it seems to look good on paper. Representative democracy is the best hybrid alternative yet invented. But it has its limitations and problems as well. Using the US Senate as an example, you will understand the problem better. Each state (regardless of size) has 2 Senators. In a small state that might mean that the 2 Senators are an accurate representation of a majority of its citizens. Delaware comes to mind. Being the smallest state, it is more likely that 2 Senators coming from that state have a better than even chance to represent most of the states interests. Take Alaska as the oposite extreme. Alaska is the largest state and also has only 2 Senators. The likelihood that those 2 Senators acurately represent the interests of the cities as well as the countryside is pretty slim. Hence the problem. While the Senators in question represent someone, they don't necessarily represent everyone or in some cases even most of the population they cover. See the problem.
The US House of Representatives is supposed to balance this equality of all states with representative numbers based upon the population of the state. This may have sounded good in 1789, but I am certain the founders never envisioned that the population would move so dramatically from the Northeast to the South and West. This means that the House has shifted over the last 30+ years to be more representative in these new areas and less where the traditional government authority resided.
Hence, special interests have cropped up over the years to represent the interests of those with the money to buy the policies they want. Sometimes these policies benefit you and I and sometimes they harm us. At best we can hope that they don't impact us at all (good luck with that thought though). This means that if a group of people (be they corporations or a professional group) that has enough money can more likely pursuade the members of Congress to change laws to benefit their interests.
Lets look at the example of a small company called Aereo. This company wants to allow people in certain cities to rent an over-the-air antenna to watch TV. On the surgace that sounds reasonable since I can put up an antenna at my house and do the same thing. The difference here is that you have to live within a certain restricted geography and you receive the TV programming over the internet (using an app for your iPad or over your computers). That is a bit of an oversimplification, but that is the basic premise.
Now that sounds like a good idea to me since my antenna tends to get a little fuzzy when the wind blows hard or it rains. Not having to rely on my own equipment would be great. The programming is available to anyone who wants to put up the antenna so there should be no problem. I am just renting someone elses antenna and watching TV. Unfortunately, the TV networks don't see things this way. They are paid fees by the cable company to carry their channels even though those same broadcasts are available for free over the air. Aereo doesn't pay the networks to broadcast these channels and there is the rub. The networks have sued Aereo in each city they operate. They feel that they should get paid and if they don't get paid they are going to move all of their programming to paid cable channels and just use the over the air channels to put out public access programming. So if you want to watch any primetime programmaing you will need to get a cable subscription to see your show. How rude?
Now the networks are lobbying congress to change the laws to close the loophole that allows Aereo to exist. They will probably be successful since they have deep pockets and a long-standing relationship with the government. What has not been talked about is the spectrum that these networks use? You see the government gave the spectrum (that is the radio or TV band that brings those wonderful shows to your antenna and then to your TV or radio) to these networks at the beginning of the 20th century. That's right, in an effort to commercialize and create a "public beneft" the goverment liscensed this spectrum to small companies that eventually became ABC, CBS, NBC and FOX. We the people gave these groups the right to exist and now they wish to remove our ability to see their programming.
The government of the people, for the people and by the people doesn't truly exist in the above example. This is just one example of many that occur daily. If you think WE are in charge, how mistaken you are. IF you think the US Constitution still applies then make everyone in the government know what you think. We are a nation of laws and traditions, but I don't belive the founders from 1789 would recognize the country they founded. We no longer control the governement, it controls us. Stand up and be counted. Stand up for what you believe. You may be standing alone for a time, but you won't be alone for long. There is truly safety in numbers, but the number has to start as one. Will you be that one in your community? Start with your own home. Don't patronize companies, organizations or policial groups that don't represent your beliefs. DO patronize those that do. It isn't always black and white, but getting into the gray in life can lead down the road to justification of bad decisions that lead to worse decisions. Check out this video put together about the wisdom of our founding fathers and determine if we can get back to these principles in your lifetime. We are only cheating our children and grandchildren if we don't.