Chris Dodd has introduced a bill to the Congress to cap the number of troops to Iraq and stop any more troops being sent without the explicit approval by Congress.
"Senator Dodd's bill does not seek to cut off funding for American troops currently in harms way. Rather, it argues that the 2002 resolution has run its course. If the President wants to escalate our military commitment to Iraq and if the President wants to send more troops into the center of a civil war, then the President must make that case to the United States Congress and let the full Congress vote on the merits of such a plan."
Read the statement or have a look at the draft bill here.