Democrats² in the US Senate say they have now secured the votes they need to begin a full debate on a bill designed to overhaul³ healthcare provision.

美国参议院民主党成员称，他们准备就医疗改革方案进行一场全面的辩论。

Mr Reid's bill is more than 2,000 pages long

Two Democratic senators whose support had been in doubt say they will now back the move, assuring the party the 60 votes needed to pass the measure.

The 100-member chamber's 40 Republicans will unanimously（全体一致地） vote against it.

President Barack Obama has prioritised（优化） the reform, designed to secure coverage⁴ for millions of uninsured Americans.

Senate Democrat¹ leader Harry⁵ Reid's proposed $849bn (£508bn) bill would extend coverage to another 31 million people, or 94% of eligible⁶（有资格的，合格的） citizens, he said on Friday.

The legislation, which was outlined in a 2,074-page document, is said by Democratic aides to reduce deficits⁷ by $127bn (£76bn) over a decade and by as much as $650bn (£389bn) in the 10 years after that.

But it has been criticised by Republicans as being too expensive. They say they will block it, and debate is expected to be fiery（热烈的，暴躁的）.

Anything less than 60 votes for the initial measure will leave the bill vulnerable to Republican delaying tactics（拖延时间战术）.

Need for debate

Efforts to get it passed had focused on three centrist（中间派议员） Democrats - Ben Nelson of Nebraska, Blanche Lincoln of Arkansas and Mary Landrieu of Louisiana - who expressed doubts about the bill.

Senator Nelson backed the procedural vote on Friday, but Senators Lincoln and Landrieu only declared themselves hours before it was due to take place.

Senator Lincoln said that it was important to start debating the issue. All three continue to have deep reservations about the bill itself.

Correspondents say that if the measure fails at the first hurdle⁸, it might not be the end of the bill but would push it well into next year.

It would also cast doubt on whether the Democrats will be able to find any genuine consensus⁹（一致，合意） on a final bill, they say.

The House of Representatives narrowly passed its own version of the reforms earlier this month.

Medicare cuts

Mr Reid opened the session by presenting highlights of the plan. A vote is not expected before 2000 local time (0100 GMT on Sunday).

Patrick Leahy, a Democrat from Vermont, said it was vital to back the bill.

"The country suffers when there is a failure to act on serious challenges that millions of ordinary Americans face in their daily lives," he said.

But Republican leader Mitch McConnell urged Senators to vote against "this staggering（犹豫的，惊人的） spending programme at a time when many would argue our international bankers, the Chinese, are lecturing us about debt".

Under the bill, most Americans would have to have health insurance, while private insurers would be banned from refusing to provide insurance because applicants¹⁰ had pre-existing medical conditions.

Insurance would be made more affordable¹¹（支付得起的） with subsidies¹²（补助金，津贴） available to help those in lower income bands, the Democrats say.

People would also be able to take part in new insurance market places and be able to choose to buy government-sold insurance from 2014, a provision（规定，条款） intended to help regulate the prices charged by private companies.

Large companies would be required by law to provide coverage to staff. The costs would be covered by government cuts on future Medicare spending.

If the Senate passes its bill, it must then be reconciled with（与……和解） the House of Representatives bill and voted on again before the programme can become law.

Mr Reid's bill differs to the House bill in that he calls for an increase of a half percentage point in Medicare payroll¹³ tax（就业税，薪工税） for people with an income of over $200,000 (£119,779) per annum（年） - rising to $250,000 (£149,724) for couples.

There is also a tax on high-value insurance policies that is not contained in the House version of the bill.

If approved, the legislation could lead to the biggest changes in American healthcare in decades.