Bite your tongue. Colin Powell has never been supportive of this President and it's about time someone reminds him that he's not in office anymore and needs to shut up.
Think for a moment why these discussions are taking place in Congress now. The timing is entirely due to a Supreme Court ruling that the detainees are due a trial. To abide by the court decision, yet delay the trials, the White House sent the matter to Congress to determine what could be presented as evidence. Congress is basically determining what information gathered by what means can be used in the trials.
If Congress were to determine the issue should go back to Geneva for clarification, anything coming out of such a meeting would take considerable time, and still require it be brought back before the Senate before ratification. The whole process would likely take years, during which time additional information might be gleaned from the detainees, or others that could be detained while the issue is being resolved.
In the meantime harmony between the Senate and White House would be restored thus taking an election year issue off the Democratic table.