WASHINGTON — The gulf between President Trump’s rhetoric and a thorny geopolitical reality widened a bit further on Friday, when the White House said it would extend a decade-old executive order declaring a national emergency over the nuclear threat from North Korea.

The announcement came days after Mr. Trump declared to the world that “everybody can now feel much safer” after his meeting with the North Korean leader, Kim Jong-un: “There is no longer a Nuclear Threat from North Korea,” Mr. Trump said on Twitter.

Apparently, there still is.

“The existence and risk of proliferation of weapons-usable fissile material on the Korean Peninsula and the actions and policies of the government of North Korea continue to pose an unusual and extraordinary threat to the national security, foreign policy and economy of the United States,” read the notice, delivered through the press secretary on Friday.

The national emergency regarding North Korea has been in place since 2008, spanning three presidencies. Now it is a measure that will effectively help keep in place what Mr. Trump has referred to as “maximum pressure” on North Korea and Mr. Kim, who has said he will take steps to denuclearize the Korean Peninsula but has not begun to dismantle his arsenal of nuclear weapons. Analysts who study the country say it would be premature to declare that progress on denuclearization until that happens.