WASHINGTON -- Amid the burgeoning debate and partisan finger-pointing over North Korea's nuclear weapons program, former national security officials say that missed opportunities over the past three administrations - Republican and Democratic - could have ended or significantly stunted Pyongyang's effort.
"It doesn't mean it's our fault, but it means we have missed opportunities to head it off," said Jon Wolfsthal, who was an Energy Department monitor at North Korea's Yongbyon nuclear complex during the Clinton administration.
President Bush defended his administration's diplomatic efforts to contain North Korea's nuclear effort, countering Democrats' charges that his policy had failed and arguing that President Bill Clinton's strategy "did not work."
Bush's remarks yesterday were gentler than those Tuesday by Sen. John McCain, an Arizona Republican, who called Clinton's approach to North Korea "a failure."
Within an hour of Bush's Rose Garden news conference, Democrats countered via conference call.
"It is not a time for partisan finger-pointing," said Wendy Sherman, who was Clinton's adviser on North Korea.
"We quite understand why some in the Republican Party have decided to lash out at the Democrats," she said, describing Clinton's policy as "very tough, constructive engagement."
After World War II, development of an atomic bomb spelled survival for then-leader Kim Il Sung. His son and successor, Kim Jong Il, sees the "nuclear scepter" as crucial to keeping his family in power, Wolfsthal said.
In the 1950s and 1960s, North Korea entered into nuclear cooperation agreements with the Soviet Union and built a research center in Yongbyon, 60 miles north of the capital, Pyongyang. In 1965, the Soviet Union gave North Korea its first research reactor, and Pyongyang built a modest unit that became operational in 1986.
As it watched the developments, the U.S. government pressed Moscow to coax North Korea to join the Nuclear Non-Proliferation Treaty, which would subject it to international inspections. North Korea ratified the treaty in 1985, but a squabble over paperwork delayed implementation of safeguards and inspections until 1992.
In 1989, the Yongbyon reactor was taken off-line for about 100 days, and U.S. intelligence officials believe that the North Koreans separated out plutonium for reprocessing. Estimates vary, but many experts believe North Korea obtained enough plutonium at that point to make one or two bombs.
"We didn't do anything," said Wolfsthal. "History is going to show that was a tremendous turning point."
Had the United States acted, he said, North Korea could have been required to suspend nuclear activity or put it under international safeguards.
At the time, there was considerable debate within the first Bush administration over whether to act, Wolfsthal said, but the White House ultimately rejected calls for action.
The next opportunity came five years later.
In 1993, North Korea refused to allow the International Atomic Energy Agency to conduct special inspections of some of its facilities and threatened to withdraw from the treaty.
Tensions escalated, and in 1994, Clinton began making contingency plans for a possible military strike on the Yongbyon facility, said Matthew Bunn, who worked on nuclear security issues in the Clinton White House.
The secretary of defense went to China to alert leaders to U.S. plans. Clinton sent bombers to Guam, said Bunn, now a nuclear security specialist at Harvard University.
But those plans were set aside when former President Jimmy Carter flew to North Korea in June 1994, Bunn said. The talks led to an agreement signed in Switzerland that October.
Under the deal, North Korea agreed to halt its nuclear program and the United States said it would help replace North Korea's reactors with light-water power plants. The countries also agreed to move toward normalizing political and economic relations.
"Both sides failed to fulfill their obligations," Bunn said.
Toward the end of the Clinton administration, the United States came close to reaching an agreement to halt North Korea's development of ballistic missiles, said Mark Fitzpatrick, a former assistant secretary of state for nonproliferation in the Bush administration, who left last year.
Meanwhile, North Korea began acquiring centrifuge equipment to enrich uranium from Pakistani nuclear scientist Abdul Qadeer Khan, which violated the 1994 agreement at least in spirit, Fitzpatrick said.
Nuclear bombs can be made with plutonium or highly enriched uranium. U.S. intelligence agencies reached consensus in 2002 that North Korea was trying to enrich uranium.
The third turning point, former officials said, was Bush's famous "axis of evil" declaration in his 2002 State of the Union address.