Trump has ordered the Navy to rip out the modern jet-launch systems on its newest carriers and put older steam ones back in — a costly step backward that hands China an edge.

• Trump directed the Navy to replace the new electromagnetic catapults on its Ford-class carriers with older steam versions, which could cost millions or billions.
• The steam system needs far more sailors to run — 12 versus two — at a time when the Navy is short about 20,000 people.
• The switch will hit the USS Doris Miller first, a carrier already two months behind schedule and with the newer system half-installed.
• China already uses the modern electromagnetic system on its newest carrier, so the U.S. is giving up an advantage it had.
• The order also scraps advanced weapons elevators for older hydraulic ones, and it traces back to a single conversation with one sailor in 2017.

Outlook: If carried out, the change will delay carrier construction and waste billions to install worse technology.