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 Barack 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.
The Senate twice on Monday rejected House-passed bills that first sought to delay key portions of the 2010 "Obamacare" law, then to delay the law's requirement that millions of people buy medical insurance. Early Tuesday the House named negotiators for what would be a Senate-House conference to work out differences on the bill. The Senate rejected that gambit.
As the standoff continued, some Republicans voiced nervousness.
Republican Rep. Tom Cole of Oklahoma called the shutdown "a big mistake." Interviewed on MSNBC, Cole called on House and Senate negotiations to end the impasse.
The order directing federal agencies to "execute plans for an orderly shutdown due to the absence of appropriations" was issued by White House Budget Director Sylvia Burwell shortly before midnight Monday.
The spending bill at the center of the fight would fund the government only through Nov. 15 if the Senate gets its way or until Dec. 15 if the House does — and even an agreement to reopen government temporarily might do little to fix the underlying standoff.