In about two dozen states across the country, the insurance marketplaces at the heart of the 2010 health-care law remain in limbo, with Republican governors or lawmakers who oppose the statute refusing to act until the Supreme Court decides its constitutionality.

New Jersey’s Republican governor, Chris Christie, joined the ranks Thursday, vetoing a bill from the majority Democratic legislature that would have set up the Garden State’s version of the “exchanges,” through which individuals and small businesses could shop for insurance.

In states with Democratic governors, such as New Hampshire and Minnesota, it is often Republican-dominated legislatures that are causing the hold-up. And in six states where Republicans hold both branches of government, including Kansas and South Dakota, state assemblies haven’t even considered laws to establish the marketplaces.

Though the battles primarily break along partisan lines, there have been at least a half-dozen exceptions. Last spring, the Republican governor of Nevada chose not to stand in the way of an exchange bill adopted by the majority Democratic assembly. And the Republican insurance commissioner of Mississippi is using existing authority to set up an exchange with the blessing of the Republican governor.

Meanwhile, Democratic lawmakers in a few states — including Arkansas — have proved unwilling to push for an exchange.

And in some states the delay has been caused by disagreements over technical details rather than principle.

The gridlock could continue for months even if the Supreme Court upholds the law, predicts Cheryl Smith, a consultant with the conservative firm Leavitt Partners, which is working with a number of states on their plans.

The court is expected to rule late next month. But even if the law survives that challenge, many officials opposing it will still want to wait on the outcome of the November elections — banking on a sweep of both the presidency and Congress to empower Republicans to repeal or revise the law.

Until then, said Smith, state GOP leaders will be loathe to take steps that could be construed as legitimizing a statute they argue is fundamentally unsound.

“This does not end in June,” Smith said.

The approach could leave state officials little time to adapt if neither the court decision nor the elections go their way: Although the exchanges won’t open for business until 2014, the law requires a state to prove it has made sufficient progress toward setting one up by Jan. 1, 2013 or face a federal takeover.

Political statement

The exchanges are essential to achieving the law’s goal of expanding access to insurance because they are aimed at small businesses and people unable to get coverage through an employer. The law will also provide millions of such individuals federal subsidies to buy a plan through an exchange.

Nonetheless, state lawmakers and analysts on both sides of the debate say the foot-dragging amounts to more of a political statement than a strategy with potential to derail implementation of the health-care law.