Since Trump's inauguration, the ACA marketplace has undergone multiple waves of sabotage from the administration and the Republican Congress. Leaving aside some short-term hits, such as the cutoff of advertising at the end of Open Enrollment for 2017, these are the structural elements:
- Radical reduction in federal funding for enrollment assistance and advertising
- Cutoff of direct federal reimbursement to insurers for the Cost Sharing Reduction (CSR) subsidies they are obligated to provide to low income enrollees (now priced into premiums)
- Effective repeal of the individual mandate, which requires those for whom coverage is deemed affordable to obtain it or pay a penalty (Republican Congress zeroed out the penalty)
- Regulatory promotion of a parallel market in medically underwritten short-term plans and association health plans -- measures designed to worsen the risk pool in the ACA-compliant market.
The ACA was designed to promote state innovation and autonomy, within fairly firm boundaries. While those boundaries have been breached on multiple fronts, states still have leeway to stay within them or actively reconstitute them. Meanwhile, thanks to the failure of Republicans' repeal legislation, federal funding for the core programs remains in place -- and has even been inefficiently enhanced, via the CSR funding cutoff, since reimbursing CSR is more cost-effective for the federal government than paying premium subsidies inflated by CSR.
It strikes me that New Jersey is unique in the degree to which it has acted to fend off the sabotage. Going into 2019 enrollment, the state has:
