WASHINGTON (USA TODAY) — After weeks of closed-door meetings, Senate Republican leaders Thursday unveiled a health care bill aimed at scrapping Obamacare in favor of a law that would make deep cuts in Medicaid, end the mandate that everyone buy insurance, repeal taxes on wealthy Americans and insurance companies, and strip funding from Planned Parenthood for a year.

Senate Majority Leader Mitch McConnell, R-Ky., expects the bill to come to the floor for a vote as early as next week, after the non-partisan Congressional Budget Office has estimated its cost and impact. It is not clear whether the legislation can attract enough support from both moderate and conservative Republicans to pass. Democrats are united against it, meaning that McConnell can afford to lose only two GOP votes.

GOP leaders said the bill represents Republicans' best chance to deliver on their campaign promise to repeal and replace the Affordable Care Act — President Obama's signature health care law. Republican lawmakers and President Trump have railed against the law, charging that it has raised insurance premiums and driven insurers out of the marketplace.

Democrats say that Republicans have undermined Obamacare by creating uncertainty about whether insurance companies would receive federal payments to defray the cost of offering lower-priced coverage to low-income Americans.

The House passed a different version of the bill on May 4, but senators immediately rejected it and said they would start from scratch on their own proposal. One of the biggest differences in the Senate bill is that it does away with a controversial House provision — which critics dubbed an "age tax" — that would greatly increase costs for older Americans who need subsidies to pay for medical coverage. The Senate bill would tie subsidies to income rather than age. It would, however, make it harder for people to qualify for the subsidies by tightening the income requirements.

The Senate plan does not include a House provision that would let states get waivers to allow insurance companies to raise premiums on some Americans with pre-existing medical conditions. Both the House and Senate bill would phase out the expansion of Medicaid eligibility, but the Senate bill does it more slowly.

Although President Trump celebrated with House Republicans at the White House last month when the House passed its health care bill, he later referred to the legislation as "mean" and said he hoped the Senate bill would have more "heart."

Democrats and some Republicans, including Sen. Rand Paul, R-Ky., complained that the Senate bill was drawn up in secret and warned that senators are being rushed into voting on legislation they know little about. Paul on Wednesday reintroduced his "Read the Bills" resolution that says that senators must have at least one day for every 20 pages of a bill to study the legislation before it can be brought to the Senate floor.

"Legislation is too often shoved through Congress without proper hearings, amendments, or debate, as the secrecy surrounding the Senate’s health care bill and the pressure to vote for it with little time to fully evaluate the proposal once again remind us," Paul said.

Sen. Claire McCaskill, D-Mo., said on MSNBC on Thursday that the bill's chances of passing are 50-50.

"I think it's a coin flip," she said.