New Delhi, June 30 -- US President Donald Trump's vision of joining Mount Rushmore's monumental ranks has reemerged since his return to office, rekindling debate over whether the Black Hills sculpture could be altered to feature a fifth president. But geologists, historians, and park officials agree: despite political enthusiasm, the combination of fragile rock, structural risks, and artistic precedent makes the idea all but impossible.

Four presidents are already immortalized on Mount Rushmore: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. The notion of adding Donald Trump's likeness has reemerged since his return to office, after a Congresswoman from Florida Anna Paulina Luna introduced a bill in January...