From the LA Times:
The compromise legislation, which is racing toward the White House, authorizes the president to seize American citizens as enemy combatants, even if they have never left the United States....It also allows him to seize anybody who has "purposefully and materially supported hostilities against the United States." This grants the president enormous power over citizens and legal residents. They can be designated as enemy combatants if they have contributed money to a Middle Eastern charity, and they can be held indefinitely in a military prison.
Not to worry, say the bill's defenders. The president can't detain somebody who has given money innocently, just those who contributed to terrorists on purpose.
But other provisions of the bill call even this limitation into question. What is worse, if the federal courts support the president's initial detention decision, ordinary Americans would be required to defend themselves before a military tribunal without the constitutional guarantees provided in criminal trials.