North Koreans gathered at Kim Il Sung Square in Pyongyang on Monday to celebrate the launch of a satellite-bearing rocket a day earlier. The launch has further intensified talk of expanded sanctions against the country. (Jon Chol Jin/AP)

Crossing a red line. Unacceptable. Won’t be tolerated. Serious consequences.

Those are just a handful of the scolding phrases uttered over the past two decades at every bend on North Korea’s road to becoming a nuclear state, from pulling out of the nuclear Non-Proliferation Treaty and expelling inspectors to its more recent advances in weapons and missile technology.

Over the past decade in particular, since North Korea tested its first nuclear device in 2006, the international community has turned repeatedly to one means of showing Pyongyang just how angry it is: sanctions. There have been sanctions designed to stop North Korea from acquiring weapons technology and conventional arms, sanctions to block its ability to move money around the world and sanctions to prevent the ruling Kim family and its cronies from getting personal watercraft and fancy watches.

The United Nations was already considering a new round of measures to punish Pyongyang for its fourth nuclear test, conducted last month, when leader Kim Jong Un ordered the launch Sunday of a long-range rocket thought to be part of his country’s ballistic missile program.

Denunciations of North Korea’s behavior and pleas for China — a veto-wielding member of the U.N. Security Council — to get tough on the regime followed immediately, prompting a familiar sense of deja vu.

“The U.S. and North Korea are mired in a ‘tit for tat’ situation where there is a provocation by North Korea followed by a U.S. or U.N. response, followed by a North Korean response,” said Keith Luse, executive director of the National Committee on North Korea and a former top congressional aide. “The situation resembles layers of an onion.”

Although sanctions have no doubt made it harder for Pyongyang to do business, they clearly have not forced the regime to change its behavior or prevented significant advances in the North’s nuclear weapons program.

As Iran prepares to welcome international oil companies after its historic nuclear deal with the United States, Cuba welcomes American tourists and Burma comes to grips with democracy, one question continues to vex U.S. officials: How do you solve a problem like North Korea?

The Obama administration has exercised “strategic patience,” the idea — championed by Hillary Clinton while she was secretary of state — that the United States can wait for North Korea to agree to denuclearization talks.

Republican presidential hopefuls, no doubt mindful that Clinton could end up as the Democratic nominee, have denounced that policy and laid out alternative plans.

At the most recent GOP debate, which began just half an hour after North Korea launched Sunday’s rocket, former Florida governor Jeb Bush said he was not against a “preemptive strike” on North Korea, Florida Sen. Marco Rubio said North Korea should be put back on the list of state sponsors of terrorism, and businessman Donald Trump said, “Let China solve that problem.”

Analysts across the spectrum agree that the current policy appears not to have worked.

“There’s a decent consensus out there that we have no strategy. It’s very hard to find anyone to defend strategic patience,” said John Delury, an international relations professor at Yonsei University in Seoul. “We can’t just go on like this.”

But there is no appetite in Washington for engagement, and North Korea has made clear that it has no interest in talks about denuclearization. Its message has been: We’re a nuclear state now. Deal with us as such.

Military action, meanwhile, is problematic. While North Korea’s outdated military technology is no match for the United States’, it has enough artillery trained on Seoul to inflict huge damage on the South Korean capital before falling.

So what’s left? Sanctions. And in the absence of tough new punishments from the United Nations, where China and Russia typically water down multilateral action, the burden of strengthening existing sanctions falls on the United States.

“There’s lots more we can do on the punitive track,” said Bruce Klingner, a former North Korea analyst at the CIA, now at the Heritage Foundation. “We can continue to try to enforce our own laws and to constrain North Korea.”

This is a rare subject of bipartisan agreement on Capitol Hill. The House last month approved a sweeping new sanctions bill by a vote of 418 to 2, and the Senate is set to vote on a similar bill Thursday.

There are still plenty of tools left in the sanctions box, Klingner said, noting that the United States has targeted twice as many Zimbabwean entities as North Korean ones and has not designated North Korea as a primary money-laundering concern, as it did with Iran and Burma.

Even Christopher Hill, the former U.S. diplomat who brokered a 2005 agreement under which North Korea agreed to abandon its nuclear program, advises against trying to engage the regime.

“We have to take the North Koreans at their word, and they have repeatedly said that they’re not interested in negotiation,” Hill said. “They want to talk to us, but they want to talk to us as a nuclear power.”

Instead, it all comes back to China, he said. “I would like to see much more focus on a deep dive with the Chinese to see what can be done.”

Indeed, no matter how strong any sanctions may be, they count for almost nothing if China is not on board. As North Korea’s main, if reluctant, patron, China could cut off its neighbor’s access to goods, oil and financing. But even as it has supported U.N. sanctions, Beijing has still allowed enough trade and aid to get through to keep North Korea afloat.

“If North Korea realizes that the road is blocked, then they will have no choice but to turn around,” said Scott Snyder, a Korea specialist at the Council on Foreign Relations. “But can we block the road? The less China cooperates, the more difficult that challenge is for us.”

Chinese officials have not sent positive signals on the expansion of sanctions, instead urging all sides to “remain calm, act cautiously, avoid taking moves that could further increase tensions on the peninsula.”

China has long shown it prefers a contained North Korea to a collapsed North Korea that could bring thousands of the U.S. troops stationed in South Korea right up to its border.

“They suggest that the imperative for stability has trumped denuclearization,” Snyder said.

But in trying to figure out how to deal with North Korea, Snyder said, the United States has taken the wrong approach.

Washington has been sending officials to Beijing to exhort it to crack down on North Korea, he noted, while also trying to make up for China’s lack of action with unilateral punitive measures.

“We should be showing up in Beijing,” Snyder said, “and saying, ‘Hey, that’s a heck of a problem you’ve got on your hands with North Korea.’ ”

Read more:

North Korea’s rocket launch shows that Mr. Obama’s ‘strategic patience’ has failed

North Korea’s growing economy — and America’s misconceptions about it

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