A day after the Senate voted along party lines Saturday to bring President Obama's 10-year, $848 billion health care proposal to the floor, familiar fissures reopened over unresolved issues such as a proposed government-run health insurance program.

Though the vote gave Democratic leaders the ability to claim momentum, it also underscored difficult decisions that have been looming for months and that must be resolved if the Senate is to take a final vote by year's end.

"We can only see the finish line," Senate Majority Leader Harry Reid of Nevada conceded after the 60-39 vote. "We have not yet crossed it."

To secure the 60 votes he needed to overturn the threat of a filibuster, Reid bowed to requests by wavering Democrats such as Sen. Blanche Lincoln, D-Ark., who wanted 72 hours to review the bill before voting. Sen. Mary Landrieu, D-La., scored a provision that would increase Medicaid funding to her state by as much as $300 million in 2011.

Hours after the vote, dissention remained on display over more fundamental issues, such as how to pay for the legislation, whether the bill goes far enough to control costs and whether Congress should include some form of a government-run health plan, known as the public option.

Currently included in the bill is a government insurance plan similar to Medicare. The non-partisan Congressional Budget Office says up to 4 million people would enroll in that plan by 2019. The measure goes too far for Republicans and some Democrats, even though Reid crafted it to allow states to opt out in an attempt to attract more votes.

"I don't want a big-government, Washington-run operation that would undermine … private insurance," Sen. Ben Nelson, D-Neb., told ABC's This Week.

Highlighting the divide on the issue, Sen. Bernie Sanders, I-Vt., released a statement hours later in which he said, "I strongly suspect that there are number of senators, including myself, who would not support final passage without a strong public option."

Other senators had already made demands. Landrieu said she wants the bill to include larger tax breaks for small businesses offering insurance and a guarantee that premiums will not rise "between the time this bill is enacted, if it ever is, and the time it actually goes into effect."

With Republicans almost universally opposed — Senate Minority Leader Mitch McConnell called the bill a "job killer" on CNN's State of the Union— advancing the bill will require Reid to focus on the demands of a small group of moderate Democrats without alienating liberal members, such as Sanders.

Similar negotiations unfolded in the days before the Senate approved Obama's $787 billion economic stimulus package. Some Democratic senators such as Sherrod Brown of Ohio bristled at the idea of making significant changes to the health care bill for a handful of votes.

"I don't want four Democratic senators dictating to the other 56 of us and to the rest of the country," Brown told CNN.

The Senate bill, which would offer insurance to 31 million people who wouldn't otherwise have it, requires most Americans to buy coverage and provides subsidies to help low- and moderate-income families pay premiums. The House passed its version of the bill Nov. 7.

Senators will begin debate on the bill next week. Obama has called for the Senate finish by the end of the year.

"I want us to begin not only debating health care reform, but doing something about health care reform," Sen. Joe Lieberman, I-Conn., told NBC's Meet the Press. "But … I don't think anybody thinks that this bill will pass as it is."