WASHINGTON — US Senate Republicans suffered a second stinging setback in as many days Wednesday in their drive to uproot Obamacare, when a plan to repeal the health care law -- with no replacement at the ready -- failed to advance in the chamber.

The washout has left Republicans -- who only a day early rejoiced when the Senate agreed to proceed to a formal debate on health care -- struggling to find consensus on how to fulfill President Donald Trump’s pledge to scrap the 2010 Affordable Care Act.

Senate leaders have said they intend to pass a bill by the end of this week, but that path remained murky -- and the outcome in doubt.

The session adjourned on Wednesday night after a series of votes on minor provisions and with Democrats complaining that the Republicans are being cagey about what their next move will be.

In the new defeat for the Republicans, seven of their side joined Democrats in opposing a proposal which would have ended Obamacare’s insurance exchanges and its taxes on the wealthy; rolled back the expansion of Medicaid, the health insurance programme for the poor and the disabled; and ended mandates compelling individuals to have insurance and for companies to provide it.

The non-partisan Congressional Budget Office (CBO) forecast that 32 million Americans would become uninsured over the next decade should the bill become law.

The defeat came just hours after the Senate voted down a broader Republican plan to repeal and replace Barack Obama’s signature health care reforms.

It was a bleak set of outcomes for Republicans after a whirlwind session on Tuesday at which Senator John McCain, recently diagnosed with brain cancer, earned a warm ovation as he returned to the Senate to cast key votes.

While Trump had applauded Republicans for finally moving to a debate that could lead to "truly great health care for the American people," the moment of victory proved temporary.

Under pressure to emerge with tangible results, Senate Majority Leader Mitch McConnell was putting a variety of options forward.

"I know members in both parties have health care ideas they’d like to offer," he said. "If you’ve got one, bring it to the floor."

’No good way out’

Frustration was setting in with some members including Senator Ben Sasse, who raked fellow Republicans over the coals for failing to follow through on their seven-year-old promise to dismantle Obamacare.

"Make no mistake: Today’s vote is a major disappointment to people who were promised full repeal," he said in a statement.

"We still have a long, long way to go."

One new approach in order to keep the effort afloat was gaining traction: a limited dismantling of Obamacare.

The so-called "skinny repeal" would ditch the provision that fines individuals for not having insurance and companies that don’t offer it. It also would eliminate a tax on medical-device manufacturers.

The Republican leadership does not expect the pared-down bill to become law. But should it pass the Senate, it could be used as a placeholder, a basis for negotiating broader legislation with the House of Representatives.

The approach drew sharp criticism from Democrats, who have warned that an Obamacare repeal would result in deep cuts to Medicaid and prohibitively high insurance premiums for people with pre-existing conditions.

Top Senate Democrat Chuck Schumer warned his party will offer no more amendments until he knows what the chamber will be voting on next.

"Certainly we’re not going to do that while there is some secret legislation -skinny repeal, its reported -- waiting to emerge from the leader’s office," Schumer told the chamber.

The CBO analysis for a ’skinny repeal’ is 16 million Americans losing their health insurance and millions more seeing their premiums go up by 20 per cent, Schumer said.

And a bipartisan group of US governors sent McConnell a letter also saying a ’skinny repeal’ would be a mistake.

The House passed its Obamacare repeal and replace bill in May, but it stalled in the Senate, which was intent on crafting its own version.

The two would need to be reconciled and a final bill passed by both chambers before it reaches the president’s desk.

But with deep fissures within the Republican Party, a failure to approve any health reform plan remained a possibility.

With the pressure building, the White House sounded vexed about Republicans’ powerlessness, especially since the party controls both chambers of Congress.

Trump is "hoping they’ll join him in pushing forward a lot of the policies that most of those people campaigned on, like repealing and replacing Obamacare," White House spokeswoman Sarah Huckabee Sanders said.

Republicans need to "step up to commitments that they made during the campaign and since being elected." — AFP