WASHINGTON • Republican lawmakers were left scrambling yesterday to salvage their years-long campaign promise to repeal and replace Obamacare after their latest plan sank in the Senate, rattling financial markets and sending the US dollar to a 10-month low.

The Senate Republicans' second attempt at a healthcare Bill collapsed on Monday as two more senators refused to back it.

Senate Majority Leader Mitch McConnell said he will instead seek a vote on a simple repeal, delayed by two years to give lawmakers time to seek a replacement.

The failure to repeal and replace the Affordable Care Act is the biggest failure for President Donald Trump and the party, which controls both chambers of Congress, since their election victory.

Senators Mike Lee of Utah and Jerry Moran of Kansas said they will not support the Republican measure because it does not go far enough to address the rising cost of healthcare. They joined senators Rand Paul and Susan Collins in announcing opposition to the proposal, leaving Mr McConnell two votes short of the number needed to advance the measure amid unified Democratic resistance.

Mr Moran criticised the way the Bill was written through a "closed-door process" and said the Senate must "start fresh" with open hearings and debate.

Mr Lee said the current version does not repeal Obamacare taxes and regulations or lower insurance premiums.

The near-simultaneous statements from the two suggested a coordinated attempt to make sure neither would be singled out as the senator who dashed Mr Trump's plans. Both senators do not face re-election until 2022, making it hard for the President to retaliate against them.

With four solid votes against the Bill, Republican leaders now have two options.

They can try to rewrite it in a way that can secure 50 Republican votes, a seeming impossibility since the defecting senators are not suggesting small changes to the existing Bill but a fresh start.

Or they can work with Democrats on a narrower measure to fix the flaws in Obamacare that both parties acknowledge.

Mr McConnell conceded on Monday that "the effort to repeal and immediately replace the failure of Obamacare will not be successful". But he said he would move to pass a measure to repeal Obamacare now, then work on a replacement over the next two years.

That too has almost no chance to pass, since it could leave millions without insurance and leave insurance markets in turmoil.

Mr Trump was not ready to give up. He immediately took to Twitter to say: "Republicans should just REPEAL failing ObamaCare now & work on a new Healthcare Plan that will start from a clean slate. Dems will join in!"

Yesterday, he tweeted that he has always backed letting "Obamacare fail" and then coming together for "a great healthcare plan".

The US dollar sank yesterday to a 10-month low against a basket of major currencies, in a market deeply worried by the pace of US growth.

Polls have shown that Obamacare remains popular among Americans. A survey by the Washington Post and ABC News released on Sunday found 50 per cent of respondents prefer former president Barack Obama's programme, compared with 24 per cent who prefer the Republican plan.

In January, the non-partisan Congressional Budget Office said in a report that a repeal of Obamacare would increase the number of people without health insurance by 18 million in the first year. That number would grow to 32 million by the year 2026, and premiums would double in that time, it said.

BLOOMBERG, NYTIMES, WASHINGTON POST, REUTERS