* Combative tone in White House appearance
* Obama to Republicans: "Don't shut down the economy"
* Republicans slam "grandstanding from president"
By Steve Holland and Mark Felsenthal
WASHINGTON, Sept 27 President Barack Obama warned congressional Republicans on Friday they were on the brink of triggering a government shutdown and a historic debt default and urged them not to "burn down the house" to try to extract budget concessions from him.
Obama made an appearance in the White House briefing room to push for Congress to end its infighting as twin deadlines loom: The federal government will run out of cash on Tuesday unless Congress approves a spending bill to keep it open, and will default on its debts if the U.S. borrowing limit is not extended by Oct. 17 at the latest.
Republicans are using both deadlines to try to extract concessions from Obama and his Democrats, including a delay in the healthcare law that informally bears his name, "Obamacare."
"Our message to Congress is this: Do not shut down the government. Do not shut down the economy. Pass a budget on time. Pay our bills on time. Refocus on the everyday concerns of the American people," Obama said.
His appearance was in line with a strategy to deal with the threat of a government shutdown and default at a distance, denouncing lawmakers he feels are responsible and avoiding getting caught in a crossfire between conservative and centrist Republicans.
Republicans have spent much of the past week attacking each other, leaving House of Representatives Speaker John Boehner without a unified following.
Obama made clear he did not intend to get involved in negotiations with congressional leaders. In similar recent budget battles, he engaged in exasperating talks with Boehner, the top Republican in Congress.
In this case, he has resolutely refused, rejecting any attempt by the conservative wing of the Republican-led House to negotiate over funding his signature healthcare law or other spending measures they would like to cut.
"There will be areas where we can work together. There will be areas where we disagree. But do not threaten to burn the house down simply because you haven't gotten 100 percent of your way. That's not how our democracy is supposed to work."
He and the White House have engaged in increasingly strong rhetoric as the week has progressed. White House senior adviser Dan Pfeiffer raised eyebrows on Thursday by telling CNN the White House would not negotiate "with people with a bomb strapped to their chest."
'NO TIME TO NEGOTIATE'
Obama accused Republicans of "political grandstanding," a reaction to conservative Republicans like Texas Republican Senator Ted Cruz, whose 21-hour Senate floor speech earlier this week was mostly an attack on the healthcare law but also included a reading from Dr. Seuss' "Green Eggs and Ham" children's book.
"I don't know how I can be more clear about this. Nobody gets to threaten the full faith and credit of the United States just to extract political concessions. No one gets to hurt our economy and millions of innocent people just because there are a couple of laws that you do not like," Obama said.
White House officials say Obama is open to negotiating with Congress about spending priorities. But a senior official added, "Obviously between now and Oct. 1, there is no time to negotiate."
As a result, Obama backed a Senate vote for a short-term spending measure to keep the government running in order to buy some time.
He urged the House to follow the Senate's lead, but a spokesman for Boehner made clear that would not happen.
"The House will take action that reflects the fundamental fact that Americans don't want a government shutdown and they don't want the train wreck that is Obamacare. Grandstanding from the president, who refuses to even be a part of the process, won't bring Congress any closer to a resolution," said Boehner spokesman Brendan Buck.
Obama and Boehner have not spoken since the president issued a stern warning to the speaker in a phone call last Friday that he would not negotiate over the debt limit.
Obama's no-negotiations strategy carries some risks. He could shoulder some of the political fallout for a shutdown or a debt default in spite of his efforts to lay the blame at the Republicans' feet.
The president's job approval rating has sagged in recent weeks, under the weight of his battle with Republicans and his zig-zag policy on Syria, first threatening military action over the use of chemical weapons before seeking a diplomatic solution.
A CBS News poll this week said Obama's approval rating had dropped to 43 percent, the lowest since March 2012, against 49 percent who disapproved.
Analysts say the approach that Obama is taking to the latest budget battles is about the only one available to him.
"It is practically speaking the only thing he can do," said Norm Ornstein, a political analyst at the American Enterprise Institute. "Let's face it, what they're asking for now is a huge laundry list of things unrelated to the debt."