*Healthcare repeal likely blocked in Senate
*Law under assault on number of fronts
*Fate likely to be decided by Supreme Court
WASHINGTON, Feb 2 (Reuters) - U.S. Senate Democrats said they had enough votes to block a Republican bid on Wednesday to repeal President Barack Obama's healthcare overhaul, likely leaving the law's fate to the U.S. Supreme Court.
Senate Democratic leaders said they would stop a Republican measure to rescind the law that aims to provide more than 30 million uninsured Americans with medical coverage while requiring nearly all to be insured or pay a fine.
"I expect the overwhelming majority of Democrats to vote against (repeal)," said Senator Charles Schumer.
All 47 Republicans in the 100-member Senate planned to vote for repeal, according to the Republican leadership, but that would fall well short of the needed 60 votes.
The Senate prepared to vote on the measure just two days after a federal judge struck down the year-old law as unconstitutional, a ruling that the Obama administration promptly announced it would appeal.
The Republican-led House of Representatives, in keeping a campaign vow, voted to repeal the healthcare law last month.
Senate rejection of repeal means the embattled law's fate will be decided by court challenges and eventually the U.S. Supreme Court, a process that could extend into next year.
A federal judge in Florida on Monday ruled that Congress overstepped its authority in requiring that nearly all Americans obtain insurance or pay a fine. [ID:nN31244933] [ID:nN01120459]
The ramifications for the health sector have been widespread, affecting Aetna Inc (AET.N), WellPoint Inc WLP.N and other health insurers as well as drugmakers, device companies, and hospitals.
States, struggling to balance their books in the aftermath of the recent economic downturn, also face higher costs for the Medicaid health program for the poor.
Democrats say the law benefits people who had been unable to obtain coverage and ought to be maintained and improved.
The Senate Judiciary Committee on Wednesday held the first congressional hearing on the constitutionality of the law.
Republican Senator Charles Grassley, a one-time participant in drafting the law who later withdrew from negotiations, said it was unclear what the Supreme Court may decide.
"What is clear is that if this law is constitutional, Congress can make Americans buy anything that Congress wants," Grassley said.
Democrats say they believe the Supreme Court will ultimately decide in favor of the law.
Assistant Senate Democratic Leader Dick Durbin said a number of landmark laws, including the 1964 Civil Rights Act and 1935 Social Security retirement program, ran into trouble in lower courts before being upheld by the Supreme Court.
"I believe the same will happen with the Affordable Care Act," Durbin said of the law being challenged in many courts.
"For those keeping score, 12 federal district court judges have dismissed challenges to the law, two have found the law to be constitutional and two have found the opposite," he said. (Reporting by Donna Smith and Thomas Ferraro ; Editing by Vicki Allen)