Former President Barack Obama’s National Security Advisor Susan Rice admitted on Thursday that, over the course of Obama’s two terms in office, his administration failed to stop the communist North Korean government from building its nuclear weapons capability.

“You can call it a failure,” Rice told CNN. “I accept that characterization of the efforts of the United States over the last two decades.” But she also said other administrations were not able to put a stop to it.

The Washington Examiner reported on the interview, noting that Rice served as the U.S. ambassador to the United Nations and was Obama’s top national security adviser from 2013 to 2017.

“She said each administration has tried a range of measures, from sanctions and pressure, cooperation with China, and ‘other methods that we shouldn’t speak about on television,’ to no avail,” the Examiner reported.

"@POTUS being unpredictable is a big asset, North Korea knew exactly what President Obama was going to do."- @jessebwatters — The Five (@TheFive) August 10, 2017

“The fact of the matter is, that despite all of those efforts, the North Korean regime has been able to succeed in progressing with its program, both nuclear and missile,” Rice said. “That’s a very unfortunate outcome. But we are where we are.”

“And we now need to decide how to proceed,” Rice said.

Rice also wrote a commentary published on Thursday in the New York Times that said President Donald Trump should soften his rhetoric and accept a nuclear North Korea.

“History shows that we can, if we must, tolerate nuclear weapons in North Korea — the same way we tolerated the far greater threat of thousands of Soviet nuclear weapons during the Cold War,” Rice wrote. “It will require being pragmatic.”

Last week, the United Nations Security Council voted unanimously to put in place new sanctions on North Korea.

In her CNN interview, Rice actually blamed the U.N. move, coupled with military exercises in the region, as making it “almost inevitable” that North Korean dictator Kim Jong Un would make threats against the United States and others.