The last two U.S. battleships -- the USS Iowa and the USS Wisconsin -- have been decommissioned and reactivated several times in their 60-year history.

Now they are facing their final deactivation and could be turned into museums.

They were last deactivated in 1991, but Congress ordered them back into reserve status five years later after determining that the Navy would have a gap in its ability to support Marine Corps land operations until early in the 21st century.

From World War II until the 1991 Persian Gulf War, support for the Marines was provided mostly by the Iowa-class battleships' 16-inch guns, which can hurl a 2,000-pound projectile 24 nautical miles.

The last ship to fire its guns in support of U.S. troops ashore was the USS Wisconsin in 1991.

Congress will decide whether to decommission the two battleships for good as lawmakers try to complete the defense authorization and spending bills. A GAO report said the Iowa and Wisconsin together cost about $1.4 million a year to maintain.

The Iowa and the Wisconsin are each nearly three football fields long. The Iowa would become a floating museum in Stockton, Calif., and the Wisconsin would become a museum in Norfolk.

Critics warn that the move could leave Marines vulnerable.

The Navy expects that most future battles will be in or near coastal waters, and that it will need ships that can deliver huge amounts of gunfire to support land operations. Cruisers and destroyers serve that purpose now, and the Navy expects the new DD(X) destroyer to take over the job when it goes into service in 2014.

"The issue here is the need to press forward with a new ship and new technology to meet 21st-century threats," said Landon Hutchens, a Naval Sea Systems Command spokesman. "The battleships performed marvelously in the 20th century, with 20th-century technology. DD(X) incorporates stealth technology, precision-guided long-range naval fire support, the capability to shoot down enemy aircraft before they can fire anti-ship missiles and high-tech command and control communications capabilities."

The critics doubt the DD(X)'s capabilities and say the Navy cannot afford to wait until the next decade.

"At present the Navy's active fleet has no effective NSFS [naval surface fire support] capability," says a statement by the U.S. Naval Fire Support Association, a group that supports reactivating the two battleships. "The Navy's attempt to rectify this serious deficiency by developing long-range 5-inch and 6.1-inch 155 mm gun systems and medium-range missiles is not adequate."

Currently, the Navy uses 5-inch guns on its destroyers and cruisers to support land operations. The battleship supporters say that only battleships can provide accurate and high-volume fire in all conditions.

-- Knight Ridder Newspapers

The USS Wisconsin is an Iowa-class battleship with 16-inch guns.The USS Iowa and its sister ship are likely to become museums.