WASHINGTON—The economy could suffer a massive hangover from the government’s efforts to rescue the financial system in the form of a soaring debt burden. But the alternatives look infinitely worse.

The $700 billion the administration is seeking from Congress as the upper bounds of what it will need to take a mountain of bad loans off the books of financial firms is certainly an eye-popping figure.

To get the funds to buy up the bad mortgage loans that have threatened to bring the financial system to its knees, the government will have to borrow. And that borrowing will come at a time when the federal budget deficit is already soaring.

The deficit for this budget year, which ends on Sept. 30, is expected to rise to $407 billion, a figure that is more than double the $161.5 billion imbalance for 2007, reflecting what the economic slowdown and this year’s $168 billion economic stimulus program are already doing to the government’s books.

The Bush administration is estimating that the deficit for the budget year that begins Oct. 1, which will cover the new president’s first year in office, will hit $482 billion, a record in dollar terms.