It wasn't to be a Fed supported program. The states would have to fund it and provide "subsidies" out of their pocket.
In the meantime, the Feds would collect a percentage on EVERY policy written AND collect the "penalties".
Passing along the mandates to the States was always an element of the fiscal gimmickry to get Obamascare to come in under the bogus amount, where the “nonpartisan” Budget Office could justify it under the useless static methods... Otherwise, due diligence would’ve been done to see how many States would likely have participated in order to build in Federal subsidies is under the law however, this would have made too much sense for a Government program, not to mention blowing the rationale right out of the water :-|