A plan to create an oil-defense barrier by dumping 100,000 tons of rock off the Louisiana coast has come to a halt because the U.S. Army Corps of Engineers and independent experts say the move would destroy existing barrier islands. That has led to heated clashes between scientists and government officials, who say researchers are criticizing their efforts without offering useful alternatives. "You don't wait weeks and weeks for studies and federal permits in the middle of a war," said Gov. Bobby Jindal. "You do what you need to do as quickly as possible to protect your land and your people."