Regardless of your political positions, whatever they may be, the NDAA is a piece of legislation which grants the President of the United States and/or the military the unquestionable executive power to secretly and indefinitely detain any American civilian without due process simply because they are a suspected terrorist. Both of the two men, Obama and Romney, who will most likely win the 2012 Presiential Election are both in favor of keeping it play. Obama signed it into law during the New Year's Eve/New Year's Day between 2011 and 2012. Here are some things you probably didn't think could be done with this power.
1: Obama could hypothetically have Mitt Romney and Paul Ryan indefinitely detained for life on the grounds that they are suspected terrorists secretly and without due process at any time before his term is up. This means his election rivals could be eliminated from the voting process whenever he wants. Mitt Romney could hypothetically do the same thing to any of his future opponents with presidential aspirations at any time once he was inaugurated.
2: The President of the United States, regardless of who that is, could hypothetically intimidate and extort both the Supreme Court and the Legislative Branch to do their specific bidding with the threat of indefinitely detaining them or any of their individual members.
3: The President of the United States, regardless of who that is, could hypothetically indefinitely detain entire corporations, banks, and other major powers like them on the arbitrary grounds that they are terrorism suspects. While I'm personally less inclined to be opposed to this idea in particular, it is highly unlikely that any president will do this to their puppet masters.
4: There are already laws in place in the United States that grant the President of United States similar powers all around the world regardless of alleged jurisdictional limits. If the president were unsatisfied with the way one country was behaving, let's say France just as a random example, they could intimidate entire governing bodies in the region to do their bidding or get arrested for life because of alleged ties to terrorism.
The NDAA and laws like it grant the President of the United States the unique position of hypothetical total world domination. Regardless of who they are they could hypothetically arrest and torture anyone for any reason at any time for as long as they want simply because it allegedly fights terrorism.