Senator Nelson: We will support the health care reform bill in the Senate.

In a press conference explaining his decision, Nelson noted that he had successfully fought off efforts to include a public option as well as the inclusion of language limiting the availability of abortions. Nelson also warned that if in conference with the House the bill is ‘materially changed’ from what he agreed to he reserves the right to withdraw his support and vote against cloture the next time around.

The House of Representatives approved similar curbs on its way to passing its own version of the legislation, but abortion-rights Democrats have vowed to strip them when the two chambers craft a final bill for Obama to sign.

“I know these limits on abortion are hard for some people to accept, and I respect those who disagree, but I would not have voted for this bill without them,” the senator said in a statement.

Nelson’s backing allowed Democrats to breathe a sign of relief ahead of a make-or-break 1 am (0600 GMT) Monday vote to end debate on Democratic Senate Majority Leader Harry Reid’s newly unveiled compromise health bill.

A tentative Democratic timeline calls for key procedural votes around 7 am (1200 GMT) Tuesday and 1 pm (1800 GMT) Wednesday, with a final passage ballot at 7 pm Thursday (0001 GMT Friday) — Christmas Eve.

If the Senate approves the bill, it would still need to reconcile stark differences with a House of Representatives plan in order to pass a final measure before Obama’s State of the Union speech in January or early February.

“Let’s bring this long and vigorous debate to an end. Let’s deliver on the promise of health insurance reforms that will make our people healthier, our economy stronger and our future more secure,” the president said in his weekly radio address.

Reid’s measure strips out a government-backed “public option” plan to compete with private insurers, but would extend coverage to 31 million of the 36 million Americans who currently lack it, Democrats say.

It would forbid insurers from denying coverage because of pre-existing medical conditions, and provide subsidies to low-income Americans.

Obama’s Republican foes have sharply criticized Reid for only making the bill public Saturday and then pushing ahead with an accelerated schedule in order to meet a self-imposed Christmas deadline.

And Republicans made good on pledges to delay the bill at all costs — forcing the Senate clerk to read the measure aloud, a process expected to take most of Saturday.

“We will do everything in our power to stop it,” vowed Republican Senator John Cornyn.

As a severe snowstorm pounded the US capital, Democrats took steps to ensure that they could call upon all 58 of their senators and the two independents who often side with them to prevail in the coming votes.

The United States is the world’s richest nation but the only industrialized democracy that does not provide health care coverage to all of its citizens, about 36 million of whom are uninsured.