As a crucial deadline arrives under the Affordable Care Act – the health insurance reforms nicknamed Obamacare – the intense opposition mounted by Republicans has had a perverse effect: the creation of a mammoth national health programme run by the federal government.

Friday 14 December was the deadline for states to submit plans to run their own insurance exchanges – a gateway for their state's residents not receiving health coverage through their employers to choose or purchase health insurance. But many states with Republican legislatures have so far refused – handing over that power by default to Washington DC under the new law.

As many as 32 states – including the second and third largest in the union, Texas and Florida – will have all or part of their insurance exchanges run by the federal government, with at least 24 of them entirely run out of Washington by the health and human services department.

It wasn't supposed to be that way. Republican objections made while the legislation was being drafted saw states given the power to administer their own schemes, rather than entrust its operation to a remote federal bureaucracy. But furious opposition in many Republican-dominated states has flipped that intention on its head.

Instead it is the Democratic "blue" states that have enthusiastically adopted health exchanges and the huge federal subsidies that come with them.

Ironically, given the outcome, it was liberal Democrats who had argued for the larger pool and lower costs of a single, national insurance exchange – but whose arguments were fiercely attacked by Republicans claiming that states would be disenfranchised.

As of deadline day, states fall into three categories. There are those, such as California, New York and the District of Columbia, that have agreed to run their state exchanges, and will receive federal funding. Then there are those, such as West Virginia and Illinois, that are in a halfway house of partnership with the federal government, whether by accident or design, and will run parts of their exchange.

And then there are those states that have rejected setting up exchanges – such as Texas and South Dakota – and so will instead submit to federal control, although they have a later deadline of 15 February 2015 if they want to adopt the partnership with the government option.

In truth there is a fourth category: Florida, always the outlier. The Sunshine State has simply dragged its feet – first hoping the legal challenge it spearheaded and then the 2012 presidential election would kill off the Affordable Care Act. Since the election it has had no time to refine a blueprint.

It is most likely to default into the federally-run exchange, even if it opts to join at a later date, but no one in Florida, from the governor down, appears willing to make a definitive statement. Florida's state legislature doesn't even plan to debate setting up an exchange until its next session in March 2013.

Six Republican-denominated states appear to have taken the plunge and submitted blueprints to run their own exchanges in whole or part: Iowa, Mississippi, Idaho, New Mexico and Nevada, along with Utah, which already has a state-run health exchange of its own making.

In announcing his backing for a state-run exchange, Butch Otter, the Republican governor of Idaho, took the opposite tack to many of his comrades. "It would be irresponsible of me to simply abandon the field to federal bureaucrats. In the face of uncertainty we must assert our independence and our commitment to self-determination," Otter said.

Yet he must still overcome a hostile legislature in the staunchly Republican state.

Of the 25 states that have opted in to full federal control, only one – New Hampshire – is an unambiguously a Democratic-dominated state. But it was public unhappiness with the new healthcare reforms that forced Democratic governor John Lynch to drop plans for a state-run exchange.

With the bulk of states, and the US population, coming under the federally-run exchanges, the onus is now on Washington to set up its scheme by October 2013 for the start of individual enrolments, with coverage through the exchanges starting in January 2014 – a massive task that could determine the ultimate success or failure of Obamacare.