President Bush is voicing renewed support for Medicare's prescription drug benefit, even though the price-tag has just taken a big jump.
Administration officials acknowledge a new calculation puts the cost of the Medicare overhaul at more than 530 billion over the next decade. As he pressed lawmakers to pass it, Bush repeatedly used a figure of 400 billion.
Speaking to reporters, the president said the Medicare measure remains a "good reform", fulfilling a "longstanding promise" to help cover seniors with drug bills, while introducing elements of competition.
But he says Congress will now have to make "tough choices" in order to keep the deficit in check.
Press Secretary Scott McClellan insists the original price-tag was truthful, and came from Congress. He says the new figure comes from the administration's first in-depth calculation of the cost of a complex bill.