WASHINGTON —  An Arctic National Wildlife Refuge (search) timeline:

— 1960: President Eisenhower (search) declares that 8.9 million acres of tundra and mountains in the northeastern corner of Alaska be set aside as a protected wildlife refuge.

— 1980: Congress expands the refuge to 19 million acres and declares part of it wilderness. Also proclaims that potential oil reserves in the refuge's 1.5 million-acre coastal plain be considered for development, but only if Congress specifically authorizes it.

— 1995: Congress, using the budget process, authorizes oil drilling in the coastal plain, but President Clinton (search) vetoes it.

— 2002-2003: The House repeatedly approves drilling in the refuge as part of broad energy legislation, but the Senate rejects drilling, unable to overcome a Democratic-led filibuster.

— November 2004: Republicans gain four seats in the Senate, expanding their majority to 55. ANWR drilling advocates predict the increased GOP strength will help to open the refuge to oil development.

— March 2005: The Senate inserts into the budget a revenue provision that anticipates oil lease sales in ANWR. A Democratic-led attempt to strip the provision from the budget measure falls short 49-51. The budget document becomes a vehicle for authorizing ANWR oil drilling.