PROPONENTS OF the District’s Death With Dignity law breathed a sigh of relief when a Republican effort to block the law led by Rep. Jason Chaffetz failed. When Mr. Chaffetz later announced he would be resigning his Utah seat, there was guarded hope the matter would be quietly dropped. Then, a new low in federal meddling: President Trump included a rider in his proposed budget that would prevent D.C. officials from spending local tax dollars to give their residents a right that is exercised in six states.

No sooner was Mr. Trump’s fiscal 2018 budget released last week than it was declared dead on arrival on Capitol Hill. Unfortunately, though, it has reenergized the effort to nullify or repeal the law signed Dec. 19, 2016, by Mayor Muriel E. Bowser (D) that makes it legal for doctors to prescribe fatal medication to terminally ill residents. The measure, subject of lengthy study and debate and modeled after successful laws in other states, took effect in February after a required 30-day congressional review period. Actual implementation awaits development of monitoring and physician training systems.

Ms. Bowser has said the city plans to use funds from the current budget to develop the systems, and health officials said they would be up and running by Sept. 30. The city needs to make a priority of getting the program operational as soon as possible. It would underscore the importance of the District’s right to home rule and might make it a bit harder for Congress to undo, although given Republican animus toward the District, nothing should be taken for granted. Mr. Trump once said he wanted what was best for District residents and was even open to possible congressional representation for the District, but he has aligned himself with Republican adversaries of the city. In addition to the rider on the death with dignity law, the budget proposal also retains the current riders that block the District from spending its own funds on abortions for low-income women and marijuana commercialization.

Medical assistance in dying enjoys broad public support and other states have implemented the law with care and without abuses. If Congress persists in trying to overturn the District’s law, it not only will undermine home rule but also will deny to people with terminal illnesses the comfort of knowing they have a measure of control over their deaths. Congress should respect the rights of the District and its residents.