It wouldn’t be the first time Missouri had tried to halt the federal health care law, dubbed Obamacare.

In 2010, about 71 percent of Missourians voted to oppose the mandate to purchase insurance and in 2012, nearly 62 percent voted to prevent the governor from setting up a state-based insurance exchange.

As a result, Missouri is one of 34 states where the federal government is operating the exchange, an online marketplace that allows consumers to compare health plans and sign up for coverage.

That website, HealthCare.gov, gained notoriety because of a problem-plagued rollout last fall. As of Nov. 30, only 4,124 Missourians had selected a marketplace plan.

No data have been released to show how many of those plans included premium subsidies, but most people who use the exchange are expected to be eligible for such help.

The federal law provides subsidies for people earning up to 400 percent of the poverty level, or $78,120 for a family of three.

In Missouri, two companies are participating in the exchange: Anthem Blue Cross Blue Shield, which is operated by Wellpoint, and Coventry Health Care Inc., which was acquired by Aetna last year.