The government shutdown has reopened debate on the future of health coverage under the Affordable Care Act. Tax credits for people who get health insurance through the law expire at the end of the year. Democrats say they won’t vote to reopen the government until Republicans negotiate an extension of the subsidies. Republicans say they won't negotiate that issue until the government reopens. As lawmakers debate, a poll from The Associated Press-NORC Center for Public Affairs Research finds about 6 in 10 Americans are “extremely” or “very” concerned about their health costs going up in the next year.