BY JULIAN E. BARNES IN WASHINGTON, NATHAN HODGE IN NEWPORT NEWS, VA., AND JEREMY PAGE IN BEIJING

The USS Gerald R. Ford was supposed to help secure another half century of American naval supremacy. The hulking aircraft carrier taking shape in a dry dock in Newport News, Va., is designed to carry a crew of 4,660 and a formidable arsenal of aircraft and weapons.

But an unforeseen problem cropped up between blueprint and expected delivery in 2015: China is building a new class of ballistic missiles designed to arc through the stratosphere and explode onto the deck of a U.S. carrier, killing sailors and crippling its flight deck.

Since 1945, the U.S. has ruled the waters of ...