U.S. Senate Republican leaders struggled Tuesday to keep alive their effort to overhaul the country's key health law, postponing a vote after an independent analysis concluded that 22 million people would lose their insurance over the next decade if their proposal was adopted. Senate Majority Leader Mitch McConnell of Kentucky told his Republican colleagues he would delay a planned vote this week until after the weeklong recess centered on the July Fourth national holiday commemorating the country's 18th-century independence from England. Several Republican lawmakers had said they would not even vote to start debate on the party's proposal, which forced McConnell to drop his plan to hold a final vote by week's end before lawmakers left Washington for the holiday. Some opponents of the health law changes said the Republican plan would cost too many poor Americans their health insurance, while others thought the changes did not go far enough in overturning key provisions of the seven-year-old law championed by former President Barack Obama and popularly known as Obamacare. Two votes to spare Senate Republicans hold a 52-48 majority in the Senate. With all Democrats opposed to repealing the existing law, Republicans can lose only two supporters in order to pass their proposal, with Vice President Mike Pence prepared to cast the deciding vote in the event of a 50-50 deadlock. But at least four Republicans said they would vote against even starting debate on the plan, while others had also expressed reservations about the proposal, leaving their votes in doubt. One of the opponents, Senator Susan Collins of the northeastern state of Maine, said proposed funding cuts of nearly $800 billion in Medicaid, the government's health care program for the poor, "hurt the most vulnerable Americans" and that access to health care in rural parts of her state would be threatened. Another opponent, Senator Rand Paul of Kentucky, said it was worse to "pass a bad bill than to pass no bill." Opposition to the Republican overhaul grew Monday after the independent, nonpartisan Congressional Budget Office said 22 million people would lose their health insurance over the next decade under the Republican plan, only a million fewer than the estimate made by the CBO for the bill the House of Representatives narrowly approved last month. The CBO said Monday that the Senate bill would reduce the federal deficit by $321 billion by 2026, compared with a $119 billion reduction for the House version. Estimates for both bills expected average health insurance premiums to rise in the first two years, but fall beginning in 2020, while people pay more out of their own pocket for insurance deductibles and co-payments for health services. 'Every bit as mean' Senate Democratic leader Chuck Schumer of New York said the CBO score showed the Senate bill was "every bit as mean as the House bill." "Republicans would be wise to read it like a giant stop sign urging them to turn back from this path that would be disastrous for the country, for middle class Americans and for their party," he said. The White House criticized the CBO as having a "history of inaccuracy" in estimating the effects of health care laws. It further reiterated that President Donald Trump was committed to repealing and replacing Obamacare, saying the program "has failed the American people for far too long." Trump has assailed opposition Democratic lawmakers as "obstructionists," saying they "have no policies or ideas." "Republican senators are working very hard to get there, with no help from the Democrats. Not easy! Perhaps just let OCare crash & burn!" Trump wrote in a Twitter comment this week. No mandatory purchases Both the House and Senate proposals would end the requirement that Americans buy health insurance or pay a fine. They would phase out subsidies to help lower-income people buy insurance, curb taxes on the wealthy and cut hundreds of billions of dollars in funding over the next several years for the government's health care program for the poor and disabled. Ever since Obamacare was enacted in 2010 without any Republican votes, House Republicans have voted dozens of times to repeal it, a futile effort as long as Obama was president. But repeal of the law could be possible with Republicans in control of the White House and both chambers of Congress. If the Senate eventually approves its version of an overhaul, either the House would have to pass the same bill or reconcile its version with the Senate's before Trump could sign it into law.