Thirteen states were awarded nearly $220 million in federal grants Tuesday to help them erect the private health-insurance marketplaces that are at the heart of the 2010 health-care law — including eight led by Republican governors who opposed the legislation.

The announcement by the Obama administration brings the number of states that have received such grants to 29. It also highlights the dual path that many Republican state leaders have been following when it comes to the law — petitioning the Supreme Court to strike it down, even as they ready their states for implementation in the event that the justices uphold the statute.

Six of the states granted funding Tuesday are party to the challenge to the law: Alabama, Arizona, Idaho, Michigan, Maine and Nebraska. In New Mexico and Tennessee, Republican officials have been slow to take key steps toward setting up the marketplaces — known as “exchanges.” And in April, New Mexico Gov. Susana Martinez (R) vetoed a bill adopted by the state’s majority-Democratic legislature that would have established a state-based exchange.

The decision by Martinez and the other governors to hedge their bets by seeking federal preparation money speaks to a stubborn deadline in the law: If it stands, states that have not prepared in time will cede to the federal government key decisions about the exchanges’ setup. In a news conference Tuesday, Health and Human Services Secretary Kathleen Sebelius described state progress as “impressive,” adding: “States are moving at their own pace to get their programs up and running.”

To qualify for a final batch of federal funding, state legislatures must enact by June 29 a series of legal and budgetary authorities that few Republican-led states appear close to achieving. On Tuesday, Rhode Island became the first state granted this final “level two” funding.