U.S. Sen. Daniel Akaka has postponed a trip to Alaska to revisit his support for oil drilling in the Arctic National Wildlife Refuge, delaying a promise he made to environmentalists during his re-election campaign last year.

Akaka's pledge to visit Alaska this summer was a significant factor in the decision by the Sierra Club's Hawai'i chapter to endorse him over state Rep. Cynthia Thielen, R-50th (Kailua, Kane'ohe Bay), a drilling opponent with a strong environmental record. Arctic drilling was also an issue in Akaka's primary campaign against former congressman Ed Case, who opposes drilling.

Akaka's staff said the only time on the senator's schedule that could accommodate an Alaska visit was a weekend earlier this month. The Hawai'i Democrat planned to go with staff from the Senate Energy and Natural Resources Committee, but Alaska natives asked him to postpone because key leaders could not attend on short notice.

Akaka's staff said the trip is unlikely to be rescheduled this year and may not take place until next summer. Akaka, the chairman of the Senate Veterans' Affairs Committee and subcommittees on national parks, military readiness and federal government management, has a busy schedule this summer that includes veterans' meetings in Hawai'i during the Senate's recess.

"I am disappointed that after extensive planning by staff from the Energy Committee and my office, that my visit to Alaska was cancelled at the last minute due to requests of postponement from those on both sides of the ANWR issue, based on scheduling conflicts," Akaka said in a statement Friday. "Unfortunately, due to an extremely tight schedule, both in the Senate and in Hawai'i, I am not able to reschedule the visit to take place this summer.

"I look forward to working with those concerned to set up another date for this visit to occur."

Akaka has said he favors drilling because of a commitment he made to the Inupiat during a 1995 visit to Kaktovik, an island village that is part of the refuge. The senator, who is of Hawaiian and Chinese descent, has characterized it as a question of economic self-determination for indigenous people.

But many environmentalists say Akaka has failed to recognize the concerns of the Gwich'in Indians, who worry drilling will disrupt the calving grounds of Porcupine caribou they depend on for food.

Akaka had planned to again visit Kaktovik and hear from residents about whether they want oil and gas development on the refuge. The Gwich'in, and some environmentalists, also wanted the senator to visit Arctic Village, the closest Gwich'in village to the refuge.

"It's essential that Senator Akaka include the Gwich'in," said Lance Holter, a Sierra Club leader from Maui who was involved in some of the discussions surrounding the trip. "As much as I want him to go up there, and fly up there, and see for himself, if he doesn't visit the Gwich'in, it's a waste of time."

Although protecting the refuge from drilling is still a national priority for environmentalists, the issue is not as urgent now that Democrats who oppose drilling control the Senate and U.S. House.

Holter and others said Akaka made an effort to fulfill his promise and go to Alaska this summer but believe a visit will not have full value unless he speaks with both the Inupiat and Gwich'in.

Akaka, in his statement last year, had said he would meet with Inupiat, Gwich'in and others to evaluate the impact of drilling. "This fact-finding mission will ensure that the decisions I make in Congress continue to accurately reflect the situation on the ground and the self-determination desires of Alaska's indigenous people," the senator had said.

Arctic drilling was among the biggest policy issues, after the war in Iraq, during Akaka's re-election campaign. Many liberals backed Akaka despite his support for drilling, praising him for his overall voting record and his opposition to the war. But the Akaka campaign was concerned about how the drilling issue would play with independents. After Akaka's primary victory over Case, Andy Winer, the senator's campaign manager, acknowledged the significant risk his support for drilling posed among independents who had been open to voting for Case.

"They were weighing the environment and the war, and the war won," Winer said at the time.

Thielen, who described Akaka's announcement last year that he would visit Alaska as an "eleventh-hour promise" to appease environmentalists, said she hopes the senator will eventually go. "It's a very important trip for him to make, and I hope he finds the time to do it," she said.

Reach Derrick DePledge at ddepledge@honoluluadvertiser.com.