Coasting - By James Holmes

During a Republican presidential debate in January, GOP presidential hopeful Mitt Romney claimed that the U.S. Navy is now "smaller than any time since 1917." And so it is, in raw numerical terms. The fleet stood at 245 vessels just before Congress passed the Naval Act of 1916, launching a major expansion in case the nation entered World War I. The navy upped its total to 342 ships by 1917. The Naval Act signified a strategic decision of considerable gravity - it marked the moment when the United States resolved to transform its regional navy into a global navy without peer.

If the fleet expanded in 1916, it contracted after 1991. After approaching 600 ships during the 1980s defense buildup, the post-Cold War fleet has dwindled to about half that total. The fleet bottomed out at 278 vessels in 2007, and has hovered just over the 280 mark since. The Naval Register lists 286 ships at present. Navy leaders favor an inventory of "about 300" vessels, leaving the navy well shy of the 1917 figure.

So Governor Romney was right on the facts, if perhaps a trifle casual with them. But was his implication -- that the navy is getting too small to perform its missions -- equally correct? That's the more interesting and relevant question for anyone interested in American victory at sea. Alas, there's no pat way to answer it.

Which 300 Ships?

Despite its heavy scientific-technical character, calculating sea power is an inexact science. There is no consensus method by which to measure naval might. Counting numbers of hulls can mislead, while factoring in the operational, strategic, and even political context surrounding seafaring endeavors is paramount. Let's start with an obvious question: which 300-odd ships comprise the U.S. Navy at any instant?

Think about it. A fleet made up of 300 Coast Guard-like combatants suitable for policing the waters off North America would clearly be a less formidable, more defensive-minded creature than a 300-ship fleet heavy on aircraft carriers, guided-missile cruisers, destroyers, and other high-end vessels carrying enough offensive punch to wrest command of the sea from adversaries and project power onto distant shores.

The mix of ships and capabilities determines the navy's aggregate combat strength. And that mix is changing. For example, multi-mission frigates commissioned during the Cold War are being retired and replaced by single-mission Littoral Combat Ships (LCSs). While the LCS has its virtues, it is no frigate.

Changing out highly versatile ships for lightly armed successors will attenuate the fleet's battle capacity over time, even as fielding these relatively inexpensive platforms boosts the number of hulls in the water. That may delight those using Romney's measurement standard - brute numbers - but the fact remains the navy is substituting part of its combat power for quantity. Let's not succumb to bean-counting: Tracking trends in the makeup of the fleet, not just raw numbers of ships, is a must.