JUST days after taking control of Congress, Democratic politicians warned today that US President George W. Bush would not get a blank cheque to expand the number of US troops in violence-wracked Iraq. New House Speaker Nancy Pelosi told CBS television that the burden was on Mr Bush to justify any extra spending on the nearly four-year-old war. "If the President wants to expand the mission, that's a conversation he has to have with the Congress of the United States,'' she said. "But that's not a carte blanche, a blank cheque to him to do whatever he wishes there.'' Couching her comments by saying that the Democrats would "always support the troops who are there", Ms Pelosi warned that "the President is going to have to engage with Congress in the justification for any additional troops he may wish". "Escalation of the war is opposed by the Democrats,'' she said.