President Barack Obama plans to deal with a Dec. 31 deadline that automatically would declassify secrets in more than 400 million pages of Cold War-era documents by ordering governmentwide changes that could sharply curb the number of new and old government records hidden from the public.

In an executive order the president is likely to sign before year's end, Obama will establish a National Declassification Center to clear up the backlog of Cold War documents. But the order also will give everyone more time to process the 400 million pages rather than flinging them open at year's end without a second glance.