President Bush has proposed making Pearl Harbor a national monument alongside landmarks such as the Statue of Liberty, the Grand Canyon and Custer Battlefield.

But the consideration has left the Navy to ponder how the designation would affect an active base and shipyard seeking to modernize.

"Pearl Harbor is well known as the site of Imperial Japan's attack on Dec. 7, 1941. Its historical significance, however, both preceded the Japanese attack and spanned World War II, during which it served as the central base for our Pacific naval forces," Bush said in a White House memorandum Thursday.

While the USS Arizona Memorial serves as the final resting place for many members of the battleship's crew, other objects of historic and scientific interest, including Ford Island, lie outside the memorial, the president said.

The president directed Defense Secretary Robert Gates and Interior Secretary Dirk Kempthorne to assess the "advisability of providing additional recognition or protection" to historic sites at Pearl Harbor and elsewhere in the Pacific that played important roles in World War II.

The memo notes that much of the Pearl Harbor area lies within an active military base, and asks the defense and interior officials to "consider in your assessment that any proposed actions should limit the Department of Defense from carrying out the mission of the various branches of the military stationed or operating anywhere within the Pacific."

According to the National Park Service, the Antiquities Act of 1906 authorizes the president to proclaim historic landmarks, historic and prehistoric structures and other objects of historic or scientific interest as national monuments.

President Theodore Roosevelt designated Devils Tower in Wyoming as the first national monument.

In 2006, Bush gave the Northwestern Hawaiian Islands monument status. The 1,200-mile string of islands subsequently was designated as the Papahanaumokuakea Marine National Monument.

The National Park Service has responsibility for administering most of the monuments, but some are managed by other state and federal agencies.

Monument designation potentially could result in new constraints on development of existing leases and permits, as well as bar new leases, claims and permits, the park service said on its Web site.

Agnes Tauyan, a spokeswoman for Navy Region Hawai'i, yesterday said, "We look forward to working with the National Park Service; however, we have not yet seen their draft proposal."

Tauyan said the Navy has "a very sound working relationship with our historic partners at the USS Arizona Memorial — which is run by the National Park Service — as well as the USS Missouri Memorial, USS Bowfin Submarine Museum and Park and the Pacific Aviation Museum on Ford Island."

LANDMARK DISTRICT

Most of Pearl Harbor already is part of a National Historic Landmark district. The district focuses on the Dec. 7, 1941, attack, but also includes properties that represent the Navy's first shore establishment and the first military air facilities in Hawai'i. More than 1,200 structures lie within the landmark district established in 1964.

National Historic Landmarks are buildings, sites, districts, structures and objects that have been determined by the Secretary of the Interior to be nationally significant in American history and culture.

A nationally significant property is "of exceptional value in representing or illustrating an important theme in the history of the nation," the National Park Service said.

Properties listed on the National Register of Historic Places, by contrast, are primarily of state and local significance.

Like others, Kiersten Faulkner, executive director of the Historic Hawai'i Foundation, yesterday said she needed to learn more about the proposal to make Pearl Harbor a national monument. But she said it should be investigated.

"Working with all the tools available to us is worthy of consideration," she said.

The designation plan also leaves questions for the Navy as it moves forward with plans to modernize Pearl Harbor's shipyard. Officials have said it needs $2 billion in repairs over the next 20 years to update infrastructure built for World War I- and II-era needs and to remain competitive with other Navy yards.

The Navy plans to renovate some of those old buildings and raze others to improve efficiency.

The state of Hawai'i, the U.S. Department of the Interior and the U.S. Department of Commerce are responsible for managing the monument in accordance with the presidential proclamation that established it.