Republican senator John McCain is an avid proponent of further sanctions against Moscow. Credit:AP But McCain's absence from Washington could be longer – perhaps two weeks or more. Commenting on a description of the treatment released by the senator's office - the removal of a five-centimetre blood clot from above his left eye during a "minimally invasive craniotomy with an eyebrow incision", Nrupen Baxi, assistant professor of neurosurgery at the Albert Einstein College of Medicine, told The New York Times "the recovery time from a craniotomy is usually a few weeks". At various times in his career, McCain has refused to ride with the herd. He voted against George W. Bush's tax cuts; he went against GOP colleagues by supporting reducing greenhouse emissions and approving funding for a Barack Obama executive action that allowed some illegal immigrants to receive federal benefits; and he's also been a vocal critic of torture as a tool in the US anti-terrorism arsenal. If McCain returns to the Senate with his inner maverick to the fore, he could kill the bill, which would be a major embarrassment for the Republicans generally and for US President Donald Trump in particular.

US President Donald Trump, centre, meets with Republican senators on healthcare in June, Republican Senator Susan Collins, left, argues that the legislation is too hard on Americans. Credit:AP The GOP has spent the best part of eight years hammering the Affordable Care Act – aka Obamacare. But with control of the White House, the House and the Senate, they have been mired in factional warfare over how to proceed. Republicans managed to scrape together enough votes to get it through the House, but this latest postponement of a Senate vote is the second. Republican Senator Rand Paul is a vocal opponent of the revised bill which he says does not repeal enough of Obamacare. Credit:AP The declared holdouts are Maine senator Susan Collins, a moderate, who argues that the legislation is too harsh; and Kentucky senator Rand Paul, who claims it's not sweeping enough.

Interviewed on the Sunday talk shows, Collins declared: "There are about eight to 10 Republican senators who have serious concerns about this bill, so at the end of the day, I don't know whether it will pass." Paul was more emphatic. When asked on Fox News if McConnell had the numbers, he replied: "I don't think right now he does." Despite the GOP's success in marshalling massive voter opposition to Obamacare, the party has done the seemingly impossible by crafting a bill that has the dubious honour of being even more unpopular. One academic study ranks it as the most unpopular legislation to be put to Congress in 30 years. Despite or perhaps because of a determined Republican campaign to discredit a Congressional Budget Office report that estimates more than 20 million Americans would lose health cover under the party's plan, respondents to a weekend poll for The Washington Post and ABC News voted two-to-one - 50 per cent to 24 per cent – in favour of Obamacare over the GOP alternative. The criticism focuses in particular on Republican plans for a return to what are called "junk" insurance policies – cheap because of their very limited cover and sky-high deductibles; and funding and coverage cuts to the associated Medicaid health program.

Trump and senior Republicans have argued that consumers would get greater choice and cheaper options. But in an unlikely alliance, consumer lobby groups and health insurers are predicting the GOP plan will split the market, as healthy, younger people opt for the cheap, low cover policies, while older people will be hit with soaring costs for more comprehensive policies. The GOP plan "is simply unworkable in any form and would undermine protections for those with pre-existing medical conditions, increase premiums and lead to widespread terminations of coverage for people currently enrolled in the individual market", the insurance industry' lobbies America's Health Insurance Plans and BlueCross BlueShield Association said in a letter to all senators on Friday. The National Association of Insurance Commissioners, which represents state regulators, weighed in too, warning senators that the GOP plan "appears to block the ability of states to preserve important consumer protections, effectively oversee the plans, or ensure a level playing field". On Saturday night, the 80-year-old McCain said in a statement that after surgery at Mayo Clinic Hospital in Phoenix that he was staying home "on the advice of his doctors". When the latest draft of the bill was released last week, he complained that there was no protection for people who were now becoming eligible for Medicaid benefits.

On the secret drafting of the bill, he said in a statement: "Have no doubt, Congress must replace Obamacare, which has hit Arizonans with some of the highest premium increases in the nation and left 14 of Arizona's 15 counties with only one provider option on the exchanges this year. "But if we are not able to reach a consensus, the Senate should return to regular order, hold hearings and receive input from senators of both parties, and produce a bill that finally provides Americans with access to affordable and quality health care." Paul saw the delayed vote as an opportunity. "The longer the bill is out there, the more conservative Republicans are going to discover it is not repeal," he told CBS. "I think it's absolutely wrong," he said. "It's not at all consistent with Republican principles … We promised repeal."

Collins went the other way, telling CNN: "You can't take more than $US700 billion ($894 billion) out of the Medicaid program and not think that it's going to have some kind of effect. "This bill imposes fundamental, sweeping changes in the Medicaid program, and those include very deep cuts that would affect some of the most vulnerable people in our society, including disabled children and poor seniors. It would affect our rural hospitals and our nursing homes, and they would have a very hard time even staying in existence."