Every U.S. president in the past 30 years has tried to get North Korea to abandon its nuclear weapons quest. Yet each failed.

Chris Megerian, The Los Angeles Times

WASHINGTON — Over the last three decades, every U.S. president has used a mix of incentives and penalties in an effort to persuade North Korea’s reclusive leaders to abandon their quest for nuclear weapons.

Yet each failed, and North Korea has pushed forward with building increasingly sophisticated warheads and the ballistic missiles capable of carrying them across the Pacific Ocean.

Now Kim Jong Un, the country’s autocratic ruler, is offering to freeze his illegal weapons programs as a start to new negotiations with the United States. Here’s a look at what’s happened in the past.

— 1986

The nuclear program begins

With help from the Soviet Union, North Korea powers up a 5-megawatt nuclear reactor. The facility took seven years to build.

— 1994

An agreement with the United States

North Korea agrees to shut down the reactor, which was capable of producing fuel for nuclear weapons. In return, the United States offers to help the impoverished country build two new reactors that are capable of generating only electricity.

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— 2002

Moving toward a bomb

During his State of the Union address, President George W. Bush labels North Korea a member of an “axis of evil,” together with Iran and Iraq. Later that year, North Korean officials admit to a visiting U.S. delegation that their country has been enriching uranium, a potential fuel for nuclear weapons. The U.S.-backed construction of the two new reactors is suspended.

— 2003

Six countries start talking

North Korea withdraws from the international Nuclear Nonproliferation Treaty. But it then joins negotiations with China, Japan, Russia, South Korea and the United States, a process known as the “six-party talks.”

— 2006

Nuclear testing begins

North Korea conducts its first nuclear test by detonating a weapon underground in an isolated area. Five more tests follow, including one last September of a thermonuclear device. Leaders declare the country “a proud nuclear power.”

— 2007

Signs of progress, then backsliding

The six-party talks lead to a tentative agreement to bring North Korea back to the bargaining table to negotiate the elimination of its nuclear weapons. That same year, North and South Korea start working toward a peace treaty to formally end the Korean War, rather than the uneasy cease-fire that has been in place since 1953.

The multipronged diplomacy eventually broke down. The six-party talks were suspended, no peace treaty was signed, and North Korea pushed forward with its weapons program.

— 2017

Ready for liftoff

North Korea announces it has launched its first intercontinental ballistic missile, which the United States calls “a new escalation of the threat.” A second missile test is deemed capable of reaching anywhere in the continental United States.

But U.S. officials don’t believe Pyongyang yet has developed a nuclear warhead small enough and robust enough to survive a ballistic missile’s fiery re-entry into the atmosphere.

— 2018

New talks?

South Korean officials visited the North Korean capitol of Pyongyang this week, then made a surprise announcement after returning to Seoul that Trump will meet with North Korea’s Kim Jong Un by May.