funguy gave a good answer to the same question:
The constitution really gives the central government little power except to abide and uphold the ammendments in the constitution. The 'powers' that the central government has are a direct result of the need to have order in a democracy. Unfortunately we have come to a point once again (previously in the Cold War) that we are forced to give up our rights in the name of keeping our rights.... Doesn't make much sense does it? But there were terrorists and planes hijacked and WMD's and internet beheadings! So we are sinking our culture and our democracy to the level of the government of the one that the terrorists are more familiar with to fight the terrorists. The end never justifies the means. If you are evil for just a day for the sake of good, does that make you a good guy? What about the people that felt your evil? Wouldn't that affect their decisions and their actions? The only thing in life that is as necessary besides human rights, is a firm grasp on the laws of physics. For every action there is an equal and opposite reaction. This does not stop with the guy with the bigger stick.
Something that tends to confuse people reading the Constitution is that they miss the connection that the President's powers don't include being the chief executive of the Federal bureaucracy--which the Const. puts in the hand of Congress. This is how it was until the 1931 depression which Congress couldn't figure out how to solve/manage the problem. FDR went up on the hill and told'em, if you give ME the power to run everything, I'll get 'er done. Which, essentially, he did. The mechanism that makes this work is that Congress granted the President the power to seize control of the government for a one year period during times of emergency. Every year, the President signs a new Statement of Emergency document, thus retaining his power to run the thing. The interesting thing is what the emergency is, of course. Strip away the fancy language, the Federal government is under attack by the American people. Ya gotta love it.
read the constitution.