A senior North Korean military official stood in a dining room in Washington, D.C. and raised a glass to a senior former American military official. There was cause for celebration: It was the American's birthday, and it was the conclusion of a successful diplomatic mission.

The year was 2000 and North Korean Vice-Marshal Jo Myong-Rok was honoring U.S. ex-Secretary of Defense William J. Perry. Perry was leading a North Korean policy review for President Bill Clinton and had worked for months to drag the U.S. and North Korea closer than ever to shaping a historic agreement on North Korea's nuclear program.

Earlier Marshal Jo had met the president and passed along an invitation from North Korean leader Kim Jong Il for Clinton to visit Pyongyang.

Things were looking up.

"But it was not to be," Perry writes in his memoir "My Journey at the Nuclear Brink," a portion of which he posted on his website recently. "By then, President Clinton had only three months left in his second term. The two major foreign policy issues he wanted to address before leaving office were North Korea normalization and an Israel-Palestine peace treaty. He held both in high priority, believed that he had a chance to achieve one, but did not have time for both. He chose to spend his remaining time on a Mideast peace treaty, and almost succeeded but ultimately fell short when Yasser Arafat developed cold feet at the last minute. So sadly then, despite a determined and creative effort, President Clinton lost on both issues."

When President George W. Bush took office, Perry thought he might have another bite at the apple.

"Just six weeks after President Bush’s inauguration, South Korean president Kim Dae Jung visited Washington for reassurance that the new administration would follow through on the North Korea negotiations that I had started. Secretary Powell apparently gave him that assurance, which led to the next morning’s Washington Post headlines reading: 'Bush to Pick up Clinton Talks.'

"That same afternoon, when President Kim met with President Bush, the latter told Kim flatly that he was breaking off all dialogue with North Korea, and for two years there were no discussions with the North," Perry writes.

Perry said that he was "confused and angry as I saw our long and carefully conducted diplomacy being summarily rejected. And I was despondent at what the future would bring in Korea as this opportunity for diplomacy slipped away."

He said he appealed to then-Secretary of State Colin Powell and his deputy Rich Armitage, but nothing could be done.

"In 2000, we had the possibility (not a certainty) of reaching some degree of normalization with a North Korea that appeared ready to give up its nuclear aspirations for economic revival. By 2015 [the year of the memoir's publication] we faced an angry and defiant North Korea that had armed itself with six to ten nuclear bombs, was producing fissile material for more bombs, and was testing the components of long-range missiles. Based on those outcomes, this is perhaps the most unsuccessful exercise of diplomacy in our country’s history," Perry writes.

After the escalating rhetoric between President Donald Trump and North Korean officials last week, Perry said Thursday he's "very much afraid" now that the U.S. might "blunder" its way into a nuclear war.

"What we're doing now and what North Korea is doing now has put us on a collision course and nobody is doing anything at the moment to deflect us from that course, or even slow down the pace we're moving toward that course," Perry told The New York Times' 'The Daily' podcast. "So in a sense we're sleepwalking into a war. And I think that's a dangerous situation."