The political fallout was less predictable, especially with control of government divided and dozens of new tea party-backed Republicans part of a new GOP majority in the House. Twin government shutdowns in the mid-1990s damaged Republicans, then new to power in Congress, and helped President Bill Clinton win re-election in 1996.
This time, individual lawmakers worked to insulate themselves from any political damage. Sens. Sherrod Brown, D-Ohio, and Ben Nelson, D-Neb., both seeking new terms in 2012, became the latest to announce they would not accept their congressional salary during any shutdown. "If retroactive pay is later approved, I'll direct my part to the U.S. Treasury," Nelson said.
One day before the shutdown deadline, events unfolded in rapid succession.
In a shift in position, Obama said he would sign a short-term measure keeping the government running even without an agreement to give negotiations more time to succeed.
At the White House, a senior budget official said the impact of a shutdown "will be immediately felt on the economy."
For all the tough talk, it did not appear the two parties were too far from a deal.
Officials in both parties said that in the past day or so, Democrats had tacitly agreed to slightly deeper spending cuts than they had been willing to embrace, at least $34.5 billion in reductions.
Agreement on that point was conditional on key details, but it was a higher total than the $33 billion that had been under consideration.
It also was less than the $40 billion Boehner floated earlier in the week — a number that Republicans indicated was flexible.
There also were hints of Republican flexibility on a ban they were seeking to deny federal funds to Planned Parenthood. Officials said that in talks at the White House that stretched on after midnight on Wednesday, Republicans had suggested giving state officials discretion in deciding how to distribute family planning funds that now go directly from the federal government to organizations such as Planned Parenthood.
That would presumably leave a decision on funding to governors, many of whom oppose abortion, and sever the financial link between the federal government and an organization that Republicans assail as the country's biggest provider of abortions.
Associated Press writers David Espo, Jim Kuhnhenn and Darlene Superville contributed to this report.