Twelve of the current 17 House members who cosponsored the landmark 2009 measure known as Obamacare have signed on as cosponsors of legislation that would create a universal healthcare system, according to a MapLight analysis.

The five incumbent House Democrats who cosponsored Obamacare but who have declined to endorse a “Medicare-for-All” proposal have received an average of $209,000 in campaign contributions since 2011 from the 10 largest U.S. healthcare companies, their employees, and five major trade associations. The dozen cosponsors have received an average of $65,000 from the industry.

The disparity highlights the importance of moderate and conservative Democrats to the healthcare industry, which has united against proposals to ensure that the United States guarantees health coverage for all citizens. The U.S. remains the only wealthy nation that doesn’t offer universal healthcare, despite healthcare costs that have more than tripled over the past two decades. About $3.5 trillion, or $1 of every $5 spent in the U.S., is spent for healthcare.

The future of the U.S. healthcare system, which has higher costs and worse outcomes than other industrialized nations, has emerged as a flashpoint for the 2020 presidential election. A majority of Americans and most leading Democratic presidential candidates—with the exception of former Vice President Joe Biden—favor a universal healthcare system. The Democratic congressional leadership, however, has been reluctant to endorse such proposals for fear of an electoral backlash, similar to the 2010 midterm elections that saw Democrats lose 63 House seats in the wake of the passage of Obamacare. Meanwhile, the Republican Senate majority and President Trump have focused on dismantling Obamacare with no plan for insuring the 20 million additional Americans who have obtained health insurance since 2010.

The amounts received by the five Medicare-for-All holdouts—Reps. Joe Courtney, D-Conn.; Ron Kind, D-Wisc.; John Larson, D-Conn.; Richard Neal, D-Mass.; and Bill Pascrell, Jr., D-N.J.—were more than double the average of $92,000 in industry money received by Republican incumbents.

The Medicare-for-All measure, which was introduced in February by Rep. Pramila Jayapal, D-Wash., is cosponsored by 117 of the 235 House Democrats. None of the chamber’s 197 Republican members are cosponsoring the legislation.