Give President Trump an A for effort with his latest executive order, which tries to expand health-insurance options for individuals battered by exploding premiums and fleeing insurers. At least somebody is trying to do something after congressional Republicans failed to repeal and replace ObamaCare. While the executive order represents progress, Congress still needs to act.

Mr. Trump is directing three federal departments—Labor, Treasury, and Health and Human Services—to consider ways of providing more flexibility for association health plans, short-term insurance, and health reimbursement arrangements.

Associations have been offering their members access to various types of health coverage for decades. The best known example is AARP. Those polices are “fully insured,” meaning a licensed health insurer underwrites them and bears the risk. And because federal law before ObamaCare left insurance regulation primarily to the states, association-offered policies must comply with regulations in whichever state they’re sold.

But there is a safe harbor: the Employee Retirement Income Security Act of 1974, better known as Erisa. Widely varying state insurance regulations made it difficult for large companies with employees in multiple states to offer uniform coverage to their employees. Erisa allows large employers, as well as groups of employers known as Multiple Employer Welfare Arrangements, to “self-insure.” This means the employer, not an insurer, pays the medical bills.

Erisa pre-empted self-funded plans from state insurance regulations, so state legislatures and insurance departments have not been able to micromanage them as they do small-employer and individual plans. That freedom made self-funded plans very popular. For decades medium-size and even small employers have looked for creative ways to leave fully insured coverage for a self-funded plan.