the eventual nominee, Barack Obama. Each candidate proposed a plan to cover the approximately 45 million Americans estimated to not have health insurance at some point each year. Clinton's proposal would have required all Americans to obtain coverage (in effect, an individual mandate), while Obama's proposal provided a subsidy without a mandate. During the general election, Obama said that fixing healthcare would be one of his top four priorities as president. Obama and his opponent, Senator John McCain, both proposed health insurance reforms, though their plans differed. McCain proposed tax credits for health insurance purchased in the individual market, which was estimated to reduce the number of uninsured people by about 2 million by 2018. Obama proposed private and public group insurance, income-based subsidies, consumer protections, and expansions of Medicaid and SCHIP, which was estimated at the time to reduce the number of uninsured people by 33.9 million by 2018 at a higher cost. Obama announced to a joint session of Congress in February 2009 his intent to work with Congress to construct a plan for healthcare reform. By July, a series of bills were approved by committees within the House of Representatives. On the Senate side, from June to September, the Senate Finance Committee held a series of 31 meetings to develop a proposal. This group—in particular, Democrats Max Baucus, Jeff Bingaman and Kent Conrad, along with Republicans Mike Enzi, Chuck Grassley and Olympia Snowe—met for more than 60 hours, and the principles that they discussed, in conjunction with the other committees, became the foundation of a Senate bill. Congressional Democrats and health policy experts MIT economics professor Jonathan Gruber and David Cutler argued that guaranteed issue would require both community rating and an individual mandate to ensure that adverse selection and/or "free riding" would not result in an insurance "death spiral". They chose this approach after concluding that filibuster-proof support in the Senate was not present for more progressive plans such as single-payer. By deliberately drawing on bipartisan ideas—the same basic outline was supported by former Senate majority leaders Howard Baker, Bob Dole, Tom Daschle and George J. Mitchell—the bill's drafters hoped to garner the necessary votes. However, following the incorporation of an individual mandate into the proposal, Republicans threatened to filibuster any bill that contained it. Senate minority leader Mitch McConnell, who led the Republican response, concluded that Republicans should not support the bill. Republican Senators, including those who had supported earlier proposals with a similar mandate, began to describe the mandate as "unconstitutional". Journalist Ezra Klein wrote in The New Yorker, "a policy that once enjoyed broad support within the Republican Party suddenly faced unified opposition." The reform attracted attention from lobbyists, including deals between lobby groups and the advocates to win the support of groups that had opposed past proposals. During the August 2009 summer congressional recess, many members went back to their districts and held town hall meetings on the proposals. The nascent Tea Party movement organized protests and many conservative groups and individuals attended the meetings to oppose the proposed reforms. Threats were made against members of Congress over the course of the debate. In September 2009 Obama delivered another speech to a joint session of Congress supporting the negotiations. On November 7, the House of Representatives passed the Affordable Health Care for America Act on a 220–215 vote and forwarded it to the Senate for passage. Senate The Senate began work on its own proposals while the House was still working. The United States Constitution requires all revenue-related bills to originate in the House. To formally comply with this requirement, the Senate