A conservative challenge to President Barack Obama’s landmark health care law pushed the federal government on Monday to the brink of the first partial shutdown in 17 years.

As expected, the Democratic-led Senate rejected a measure passed by the Republican-led House to work a delay of the health plan into a temporary spending bill needed to keep the government running.

The 54-46 Senate vote came less than 10 hours before a midnight deadline to approve the funding legislation. It is now up to the House to accept a bill that doesn’t delay the health initiative -- which it has refused to do -- or find an alternative acceptable to the Senate.

If it fails to do either of those options, the government faces closures that would force 800,000 federal workers off the job without pay and rattle the shaky U.S. economic recovery.

“We’re at the brink,” said Senator Barbara Mikulski, a Democrat, as House Republican leaders calculated their next move.

Some critical services would continue during a shutdown, such as patrolling the borders and controlling air traffic.

The State Department would continue processing foreign applications for visas, and embassies and consulates overseas would continue to provide services to American citizens.

Despite no signs of a compromise, Mr. Obama insisted he is “not at all resigned to a shutdown” and he expected to speak to congressional leaders throughout the day to address the impasse. The president has vowed not to allow Republicans to use the spending bill to derail his most important domestic policy achievement.

“There’s a pretty straightforward solution to this,” Mr. Obama said at the White House. That’s for “everybody to act responsibly and do what’s right for the American people.”

The prospect of a shutdown contributed to a decline in stock markets around the world. U.S. stocks sank as Wall Street worried the budget fight could lead to something much worse for the economy -- a failure to raise the nation’s borrowing limit.

Whether or not Congress averts a shutdown, Republicans are sure to move the health care fight to a must-do measure looming in mid-October to increase the borrowing cap. The U.S. risks a market-rattling, first-ever default on its obligations if Congress fails to raise that limit.

Both a shutdown and a default would be politically risky ahead of next year’s congressional elections.

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