“It is ignorant of what constitutes national security," said retired Adm. James Loy, a former Coast Guard commandant who served as deputy homeland security secretary and TSA administrator under President George W. Bush. "They simply don’t understand the equation.”

Loy and others argue that hiring more border agents and building a wall are likely to increase the need for guarding ports and coastlines. And they contend that the Coast Guard, which intercepted more than 6,000 illegal migrants in 2016, is already overtaxed in interdicting illegal drugs and people from Central and South America while defending ports of entry from terrorist attack. Under its current budget, they say, it can’t afford to buy the new helicopters and ships it needs.