The Democratic-led Senate voted to kill Republicans' latest attempts to modify an emergency government funding bill, just hours after federal agencies and national parks began shutting down.
The Senate voted on 54-46 along strict party lines to strip the proposed amendments from the spending bill, sending a "clean" measure back to the House of Representatives that would extend funding for government agencies until Nov. 15.
The Republican-controlled House of Representatives passed the request to appoint negotiators as a last-ditch effort to avoid a shutdown that began as a midnight deadline expired.
The amendments pushed by House Speaker John Boehner also had maintained previous attempts by Republicans to modify President Barack Obama's signature healthcare law.
These included a one-year delay of a mandate for individuals to acquire coverage and a requirement that members of Congress, their staffs, and executive branch appointees acquire healthcare coverage through new insurance exchanges that started operating on Tuesday, but without any government subsidies.
Obama and his fellow Democrats have rejected any Republican efforts to use the funding impasse as leverage to change the law known as Obamacare.
After the Senate vote, there was no sign of any moves from either party toward compromise, and lawmakers simply blamed each other for the shutdown.
Senate Majority Leader Harry Reid said the shutdown made Tuesday "a good day for anarchists" in the House of Representatives.
"Speaker Boehner and his band of Tea Party radicals, they have done the unthinkable. They have shut down the federal government," Reid said on the Senate floor. "For us, that's hard to comprehend as being good. For them, they like it."
Senator Mitch McConnell, the top Republican in the Senate, said Democrats caused the shutdown.
"They've now said they won't even agree to sit down and work out our differences. They won't even talk about it. They literally just voted against working out a compromise," McConnell said on the Senate floor.
The partial government shutdown Tuesday forced about 800,000 federal workers off the job, suspending all but essential services.
The National Zoo's popular online "panda cam" went dark around 8 a.m. The White House grounds cut back to a skeletal staff. The U.S. Capitol canceled tours not personally led by Congress members.
With the Republican-controlled House and Democratic-controlled Senate at a stalemate, it was unclear how long a temporary bill needed to finance government activities would be stalled.
The No. 2 Democrat in the Senate, Dick Durbin of Illinois, called the failure to pass a budget "conduct unbefitting a responsible Congress" and said he hoped it could be resolved by the end of the day Tuesday.
"Most people in the body politic are taking a look at this and saying, 'A pox on both of your houses. It should never have reached this point,'" Durbin said Tuesday morning on CNN.
But in the House, conservative Rep. Marsha Blackburn predicted the standoff would drag on if Obama and Senate Democrats refused to negotiate over delaying a key part of the health care law.
"You may see a partial shutdown for several days," Blackburn, R-Tenn., told Fox News. "People are going to realize they can live with a lot less government."
The health care law itself was unaffected as enrollment opened Tuesday for millions of people shopping for medical insurance.
The shutdown, the first since the winter of 1995-96, closed national parks across the nation. In Washington, the Smithsonian museums website displayed a red banner noting that "all Smithsonian museums and the National Zoo are closed." Traffic was lighter and subways less crowded Tuesday morning.
Panda mom Mei Xiang could be seen snuggling with her weeks-old cub through the morning, until the Washington zoo's online feed was cutoff around 8 a.m. Care of the animals will continue.
Agencies like NASA and the Environmental Protection Agency were being nearly shuttered. People classified as essential government employees — such as air traffic controllers, Border Patrol agents and most food inspectors — will continue to work.
The White House was operating with a skeletal staff, including household workers taking care of the first family's residence and presidential aides working in the West Wing. A groundskeeper working outside Tuesday morning at daybreak said he was doing the job normally handled by four workers.
Given the shutdown, White House officials were discussing whether President Obama should change plans for a trip to Asia scheduled to begin Saturday.
The military will be paid under legislation freshly signed by Obama, but paychecks for other federal workers will be withheld until the impasse is broken. Federal workers were told to report to their jobs for a half-day but to perform only shutdown tasks like changing email greetings and closing down agencies' Internet sites.
The self-funded Postal Service will continue to operate and the government will continue to pay Social Security benefits and Medicare and Medicaid fees to doctors on time.
In a letter emailed to federal employees, Obama says the shutdown was "completely preventable." And he called on the House of Representatives to pass a law reopening the government and giving workers back pay.
The president also laments that government employees have become "punching bags" in Washington's partisan fiscal fights.
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