What would their access (to civilian courts) be without Senate action?
This is what USA Today had to say today:
In addition, the 500 or so detainees would be allowed to challenge in federal court the procedure under which they were labeled enemy combatants. The compromise proposal would allow the federal court reviews in place of the tool the Supreme Court gave detainees in 2004 to fight the legality of their detentions: The right to file habeas corpus petitions in federal courts.