WASHINGTON - Congress has less than five hours left to avert a government shutdown, setting up a late night showdown between House Republicans and Senate Democrats.

The House is set to vote around 8 p.m. on another amended continuing resolution. This one calls for a one-year delay in requiring people to buy health insurance as well as cutting subsidies for health care insurance for members of Congress and their staffs.

If the House passes its bill, the Senate is then expected to act quickly and reject - yet again - any House budget bill that dismantles Obamacare, placing the ball back in Boehner's court.

What we're watching: Will any cracks start appearing among rank-and-file House Republicans? Rep. Peter King, R-N.Y., told reporters earlier that he and up to 20 Republicans plan to vote no on the House plan, saying enough is enough.

Will Boehner suddenly cave by midnight? "Not likely," a Boehner confidante and member of Congress told ABC News. "Why would he do that now?"