Do Loose Lips Really Sink Ships?

In the wake of whistleblower Edward Snowden’s leaks about the NSA’s PRISM surveillance program, I keep hearing people roll out the old World War Two phrase “loose lips sink ships.” How literally, I wonder, are we supposed to take that? Have intelligence leaks ever led directly to the loss of a U.S. naval vessel before?

Maybe. Over the course of our naval history, there have been security breaches. At the same time, there have been ships and boats and lives lost. Most of the time, it’s very hard to draw a straight line from an instance of the former to one of the latter. There’s often correlation, but not clear causation. In one of these cases, the lips that might have sunk the ships were attached to a congressman.

During WWII, concerns about national security were probably higher than ever before in U.S. history, and secrecy was paramount to security and the war effort. Civilians were reminded of this through the “loose lips” posters, and many soldiers serving overseas were issued pamphlets that reminded them that…

Silence means security — If violation of protective measures is serious within written communications it is disastrous in conversations. Protect your conversation as you do your letters, and be even more careful. A harmful letter can be nullified by censorship; loose talk is direct delivery to the enemy. If you come home during war your lips must remain sealed and your written hand must be guided by self-imposed censorship. This takes guts. Have you got them or do you want your buddies and your country to pay the price for your showing off? You've faced the battle front; it’s little enough to ask you to face this "home front."

If only someone had given a copy of that to Andrew J. May. The Kentucky democrat served in the House of Representatives from 1931 to 1947 and chaired the House Military Affairs Committee during the war. During the summer of 1943, May and other House members visited sites in the Pacific Theater and received briefings on operations and intelligence. Upon his return home, May gave a press conference and shared a little too much of what he learned.

Americans didn’t have to worry about the safety of their submarines, he explained, because the Navy had found that the Japanese were setting their depth charges—a type of anti-submarine explosive—to detonate at shallow enough depths that the subs could avoid them. May’s comments were reprinted in various newspapers, including ones in Hawaii and other Pacific coastal areas where subs were operating.

Vice Admiral Charles Lockwood, commander of the U.S. submarine fleet in the Pacific, blamed May’s leak for leading to improved Japanese tactics and American casualties. “I hear Congressman May said the [Japanese] depth charges are not set deep enough,” Lockwood wrote in a letter to another officer. “He would be pleased to know [they] set 'em deeper now." Lockwood estimated that May’s “indiscretion” directly led to the loss of ten subs and 800 seamen.

Lockwood’s accusations and estimates might not be water-tight, though. The Navy’s “Enemy Anti-Submarine Measures” report, a summary of the Pacific fleet’s experience with Japanese anti-sub weapons, makes no mention of a change in depth charge deployment after May’s leak, and says that the Japanese were never able to figure out the full depth capabilities of American subs. Even if the depth charges were set lower, the Japanese still didn’t know how low they had to go before the subs couldn’t maneuver below them. The Naval History Division’s report of submarine losses in the war, meanwhile, does mention the use of depth charges in the attacks leading to the loss of ten subs, but the reports also couldn’t conclude the exact reasons for the loss of each of those subs. The events surrounding some losses were only learned years after the war from enemy reports or other second-hand information, and may not be entirely accurate or definitive.

Representative May, meanwhile, suffered no consequences for his big mouth except some bad press. He was later caught up in scandal, though, and convicted of accepting bribes and using his position to secure contracts and favors for a munitions company. He served nine months in prison and was pardoned by President Truman, but his political career was sunk.