Reporting from Washington -- Behind the open brawling over how to rebuild the nation's healthcare system, another struggle is beginning that may be the toughest test for the drive to cover millions of people without insurance and improve medical care for all: who should pay the eye-popping bill.

President Obama and his congressional allies -- who are also struggling to hold down the national debt after years of deficit spending and new outlays to combat the recession -- have pledged to raise more than $1 trillion over the next decade to offset the costs of what would be the biggest health overhaul in generations.