It’s not getting much attention on the campaign trail, but the U.S. Navy needs serious help. That’s the argument David Adesnik advances in a National Review Online column, one of the latest warnings that the American military is losing its edge.

The growing length of deployments is putting enormous pressure on a Navy that has fewer ships and sailors than 15 years ago, even as its responsibilities grow. The Navy hopes to relieve this pressure by building more ships, yet its plans rest on optimistic assumptions about the amount of funding that will be available in future budgets. In order for the Navy to gain relief and successfully accomplish its missions, two steps will be necessary. First and most importantly, Congress and the president should invest substantially more in the fleet. Second, the Department of Defense can mitigate the problem by basing more ships closer to potential theaters of conflict, which will increase on-station time while the Navy rebuilds.

The constant presence of American sea power, especially in the Western Pacific and the Middle East, constitutes a core tenet of the Pentagon’s approach to deterrence and crisis management. Therefore, with remarkable consistency, the Navy has kept about 100 ships forward deployed at any given time over the past two decades. Yet today’s battle fleet has 15-20 percent fewer ships than it did in the late 1990s, forcing each ship to bear a greater part of the burden. A recent report from the Center for Strategic and Budgetary Assessments (CSBA) lays out the troubling consequences of this trend.

The authors of the CSBA report, Bryan Clark and Jesse Sloman, describe in detail how longer and more frequent deployments wear down a ship and its crew. “Historically,” they write, “the Navy has planned for its ships to execute cycles consisting of a single 6 to 7 month deployment in a 24 to 32 month period.” They cite the Navy’s finding that from 2001 through 2009 each of the fleet’s surface combatants — i.e., warships other than submarines — had to spend 18 percent more time at sea. Additional time at sea translates into less time for maintenance. The more a ship deploys without sufficient maintenance, the greater the risk of serious damage. Thus, after back-to-back deployments in 2012 and 2013, the carrier USS Eisenhower had to spend almost two years undergoing maintenance, or 65 percent more time than expected.