By David Morgan

WASHINGTON U.S. House Speaker Mike Johnson faces a key test on Tuesday, as he tries to circumvent opposition by hardliners in his own Republican conference and rely on support from Democrats to pass his plan to avert a government shutdown this weekend.

Johnson, who had little senior congressional leadership experience before being elected speaker less than three weeks ago, has decided to overcome a hardline roadblock to his two-step continuing resolution, or "CR," by bringing the bill directly to the floor through a suspension of House rules.

The change allows the speaker to bypass a procedural vote to open debate on the measure, which would keep government funding levels unchanged into early next year. The House is scheduled Tuesday to vote only on passage, which would require support from two-thirds of the chamber.

More than 20 House Republican hardliners, who wanted the CR to include spending cuts and conservative policy riders such as tighter U.S.-Mexico border security, had been expected to block the debate and keep the bill from reaching the floor. More Republicans said they stood ready to oppose passage.

With a slim 221-213 majority, the Republican speaker can afford to lose no more than three party votes on legislation that Democrats oppose.

"This is the wrong approach," said Representative Chip Roy, a prominent hardliner who had vowed to block debate.

Other Republicans supported Johnson's decision to go straight to the floor. "I think the greater problem comes with a shutdown," said Representative Drew Ferguson.

To avert a fourth shutdown in a decade, the Republican-controlled House and Democratic-led Senate must agree on a CR that President Joe Biden can sign into law before current funding for federal agencies expires on Friday.

"Everybody is operating in good faith. We just ran out of time," Johnson said in an interview on CNBC on Tuesday.

But the strength of Democratic support for Johnson's CR remained uncertain.

Senate Majority Leader Chuck Schumer, Congress' top Democrat, gave only a tentative welcome to the proposal.

"For now, I am pleased that Speaker Johnson seems to be moving in our direction by advancing a CR that does not include the highly partisan cuts that Democrats have warned against," Schumer said.

Congress is in its third fiscal standoff this year, following a months-long spring impasse over the more-than-$31 trillion in U.S. debt, which brought the federal government to the brink of default.

The ongoing partisan gridlock, accentuated by fractures within the narrow House Republican majority, led Moody's late on Friday to lower its credit rating outlook on the U.S. to "negative" from "stable," as it noted that high interest rates would continue to drive borrowing costs higher. The nation's deficit hit $1.695 trillion in the fiscal year ended Sept. 30.

The Senate on Monday paused its plan to move forward on its own CR to allow the House to move first, with Schumer saying "bipartisanship is the only way to avoid a government shutdown."

Johnson's bill would extend funding for military construction, veterans benefits, transportation, housing, urban development, agriculture, the Food and Drug Administration and energy and water programs through Jan. 19. Funding for all other federal operations - including defense - would expire on Feb. 2.

House Republicans will debate the measure behind closed doors on Tuesday morning, and the outcome could further determine the path ahead of Johnson's CR - and potentially the speaker's future.

Johnson's CR formula strongly parallels the short-term measure that triggered the ouster of his predecessor, Kevin McCarthy. McCarthy used a clean CR to avert a shutdown on Oct 1. It passed with more support from Democrats than Republicans and McCarthy was voted out of his job a few days later.

Republicans say the new speaker is unlikely to suffer the same fate as McCarthy. But hardliners have been quick to see the parallel.

"Here we are. We're doing the same thing," Roy told reporters.

Lawmakers are at odds over discretionary spending for fiscal 2024. Democrats and many Republicans want to stick to the $1.59 trillion that Biden and McCarthy set in their debt ceiling agreement earlier this year. Hardliners have pushed for a figure $120 billion lower. In recent days, they have signaled a net willingness to compromise.

But the political fracas is focused on just a fraction of the total U.S. budget, which also includes mandatory outlays for Social Security and Medicare. Total U.S. spending topped $6.1 trillion in fiscal 2023.

(Reporting by David Morgan; Additional reporting by Moira Warburton and Susan Heavey; Editing by Scott Malone, Richard Chang and Chizu Nomiyama)