For three years, the Obama administration has been preparing for this moment: the launch of new insurance exchanges, intended to expand health coverage to millions of uninsured Americans.
But this is far from the grand opening that President Barack Obama may have expected.
Instead, the exchanges are starting up just as most of the federal government is shutting down, left unfunded by a Congress that's still bitterly divided about whether to discard Obama's health care law altogether.
There will be just a skeletal staff at the White House on Tuesday when Obama appears in the Oval Office to tout the benefits of his law alongside Americans who plan to purchase insurance through the exchanges. Many of Obama's aides, like hundreds of thousands of federal workers across the country, will be on furlough due to the first partial shutdown in almost two decades.
(Read more: The selling of Obamacare: Reaching the uninsured)
"Unfortunately, Congress has not fulfilled its responsibility," Obama said in a video message the White House released just after midnight Tuesday, as Congress missed its deadline to keep the government running. "It has failed to pass a budget and, as a result, much of our government must now shut down until Congress funds it again."
At the heart of the disagreement over a temporary measure to fund the government was whether Obama's health care law should be allowed to go into effect as written. House Republicans, cheered on by tea party-backed Republicans in the Senate, sought to defund or delay parts of the bill, arguing that once Americans started enrolling in the exchanges, the law will become harder to repeal.
Obama insisted he wouldn't sign a bill that gutted the law, his signature legislative achievement. Lacking funding from Congress, the White House budget office told agencies shortly before midnight to start closing their doors.
In a bit of irony not lost on the law's opponents, the main components of "Obamacare" will proceed full speed ahead despite the shutdown that will shutter national parks, veterans' centers and other government operations, starting Tuesday and lasting until Congress finds a way to break the stalemate. That's because funding for the Affordable Care Act, like other "mandatory" functions such as Social Security, air traffic control and national defense, is protected from the whims of Congress.
In his sole response to the shutdown early Tuesday, Obama directed his comments not at the lawmakers he's been scolding for weeks, but instead to members of the military. He made no reference to Republicans or Democrats, but his frustration was clear as he contrasted the professionalism and courage of American troops with lawmakers' inability to fulfill what he's described repeatedly as their constitutional duty.
"You and your families deserve better than the dysfunction we're seeing in Congress," Obama said.
Tuesday's event at the White House coincides with the digital ribbon-cutting for the exchanges, which will allow Americans to shop for, compare and purchase insurance online. The Obama administration needs millions of Americans—mostly healthy, younger people—to enroll to keep costs low for everyone.
—By The Associated Press