An investigation by Politico found that FEMA provided roughly a third of the meals, half as much water and a small fraction of tarps to Puerto Rico than it provided to Texas after Hurricane Harvey in the first nine days after the storm. Several weeks elapsed before FEMA and the Defense Department increased their presence on the island, even though airports and ports had reopened after a few days. The agencies failed to direct the aircraft carrier U.S.S. Abraham Lincoln and other ships to Puerto Rico to aid with the response. Mr. Trump remained largely out of the picture.

No president in recent memory has upended internal executive branch norms so much. In immigration, military and other matters, major executive orders have been introduced by the Trump administration without consulting with his cabinet. Agency heads have been caught off guard when policies affecting them are put into motion. The robust interagency exchange that typically characterizes complex decisions has atrophied.

All of this makes it easy for Mr. Trump to escape blame for his agencies’ missteps. But this isn’t normal. In an unwieldy bureaucracy, pressure and high-level oversight from the White House ensure that disaster response does not fall by the wayside. Where agencies are ill-equipped to handle the on-the-ground devastation and local authorities cannot fill the void, presidential leadership assumes greater import.

The Trump administration has additionally taken actions that may set back Puerto Rico’s recovery. The funding request the White House sent to Congress last November drew condemnation from both Republicans and Democrats for being too low. The administration gave Puerto Rico little choice but to adopt an experimental funding formula to rebuild its public infrastructure. The formula gives Puerto Rico flexibility during the rebuilding process but requires the island to pay for any cost overruns, putting it at risk of being on the hook for costly receipts down the road. To make matters worse, last Thursday a federal judge ruled that Puerto Ricans who have been living in motels and hotels on the mainland as part of FEMA’s temporary housing aid after Hurricane Maria have to check out on Sept. 14, possibly rendering many of them homeless.