North Korea test-fires a new missile. Some of the Pentagon’s most advanced warplanes fly over South Korea in a grim display of strength. Seoul’s new government nervously starts buying new weapons. And here at home, President Donald Trump bashes China for failing to press Pyongyang to rein in its nuclear program.

It’s been a scary few days in Washington’s increasingly scary standoff with North Korea. Taken together, the events illustrate a vexing problem for Trump and key US allies across Asia: how to keep tensions with Pyongyang from escalating out of control without turning a blind eye to North Korea’s rapidly advancing nuclear and missile programs.

The Trump administration’s preferred strategy to stop or contain North Korea depends on persuading China to use its influence to get Pyongyang to change course. China is North Korea’s biggest trading partner and routinely defends the country at the United Nations; Trump believes, correctly, that any deal with North Korea would require Chinese help. The problem is that China has given no indication that it’s willing to take a harder line with Pyongyang, leading Trump to lash out on Twitter — and leaving the White House scrambling to figure out a new approach.

It’s very important to take a deep breath: The two sides aren’t about to go to war, let alone start firing nuclear missiles at each other. For all of its bluster, North Korea has traditionally been willing to walk back from the void rather than step into it.

That doesn’t change the fact that a dangerous situation has gotten even more precarious in recent days, and there’s a reason why: Both sides are using military means to get their points across. If that continues, there’s potential for the scary situation to get even scarier.

North Korea won’t stop improving its missiles

The US and the international community have been dealing with North Korea’s missile and nuclear programs for decades. But North Korea’s missile program just got a lot better — and more dangerous — this year. "The North Korean program is a real program now," Vipin Narang, a nuclear expert at MIT, told me.

Here’s what he means. North Korea changed the game when it successfully tested the Hwasong-14 ICBM on July 4 and 28. After the second test, it appeared that the missile could travel around 10,000 km, or 6,200 miles, according to experts. That’s enough to hit the US homeland, and possibly even cities like Chicago, New York, or Washington, DC.

North Korean leader Kim Jong Un had warned that this was going to happen. Back in January, he said his country was close to testing an ICBM, a long-range missile that was a vital part of the Soviet Union’s arsenal during the Cold War. Though Trump promised that type of test wouldn’t happen, Pyongyang fired missiles not once but twice in July.

Why does North Korea want an ICBM? First, it’s a valuable deterrent. North Korea rightly believes Washington would have to think twice about using force if Pyongyang could reliably strike back. Just as importantly, the Kim regime’s primary objective is to survive — and having a viable missile and nuclear program helps it stay in power.

The Kim family, which has been in power since Kim Il Sung took charge in 1948, has seen what happens to leaders who don’t have nuclear weapons. In modern times, Iraq’s Saddam Hussein persuaded much of the world that he had restarted his country’s nuclear weapons program; he hadn’t, but the boasts helped spark the 2003 invasion that drove him from power. In Libya, Muammar Qaddafi gave up his program to build closer ties to the West, but was eventually ousted from power and killed by a mob.

So, Kim Jong Un, Kim Il Sung’s grandson, has no incentive to stop any of its programs. In fact, he has incentives to keep them going. That doesn’t leave Trump — or his predecessors — with many good options. But there is one thing the president can do in the meantime: let America’s friends in East Asia know that America will still protect them from the growing danger. Based on this weekend, it looks like he’s doing just that.

Flying bombers over the Korean Peninsula is meant to reassure US allies

In response to Friday’s ICBM test, the US flew two B-1B bombers alongside South Korean and Japanese fighter jets above South Korea on Saturday.

Kim is well aware that the US could bomb North Korea if the North were ever to attack any of those countries. But the 10-hour mission wasn’t about scaring Pyongyang. It was about letting Seoul and Tokyo know that Washington still has their backs.

"The only reason we have shows of strength is to remind South Korea and Japan that the alliance is strong,” Narang noted.

There’s a good reason the US felt it had to do this. Basically, North Korea already has the ability to strike both South Korea and Japan. They rely on the US to protect them from a North Korean missile, chemical, or nuclear attack, and they want the US to guarantee that Pyongyang will get hit if it hurts allies. The problem is that North Korea now has the ICBM, which puts at least parts of the US homeland in range.

That brings up a dilemma for the Trump administration: Does it risk being struck by North Korea in order to protect South Korea or Japan? That’s why conducting a military exercise in response to Friday’s missile test was so important.

“Our response can be viewed as necessary to assure our allies that we do still have their backs,” retired Lt. Gen. Chip Gregson, the Pentagon’s top Asia official from 2009 to 2011, said in an interview.

Flying bombers is a tried-and-true method of calming ally nerves. In 2013, for example, the US and South Korea practiced a bombing run where two American B-2 stealth bombers dropped eight fake munitions near North Korea as part of the “Foal Eagle” annual exercise. This year, Foal Eagle included around 30,000 US and South Korean troops who jointly practiced air, sea, and special operations from March to April.

In addition, the US contributes to South Korea’s missile defense. That’s why it sent the THAAD system to the country, which will help it defend against short-range North Korean missiles. It won’t stop an ICBM, but it can help protect Seoul — South Korea’s capital with a population of 25.6 million — which is within striking distance of North Korea’s large artillery force near their shared border. So far, the THAAD system has a 15-for-15 success rate in tests.

However, South Korea is thinking about building more powerful ballistic missiles of its own, the New York Times reports. The US would have to approve their construction because of their bilateral security treaty. Still, it shows that Seoul is getting nervous and is looking to take some of its security into its own hands.

That could potentially be a problem down the road. If Seoul and Tokyo ever felt like they would not be supported by the US, they might try get a nuclear weapon to protect themselves, Mira Rapp-Hooper, an Asia security expert at the Center for a New American Security think tank, told me. That has the potential to anger North Korea — and China — which would only make things more dangerous in the region.

So: Conducting shows of force with allies is not new. But it never hurts to reassure an ally. However, North Korea’s growing capabilities have added a sense of urgency.

That may be why Trump tried to get China to help with the situation. The problem is that outreach didn’t work, and now the administration is changing course.

Trump is bashing China because Beijing didn’t do what he wanted

On its face, Trump’s analysis of North Korea makes some sense. China is North Korea’s largest trading partner. If Beijing squeezed Pyongyang by cutting off its main source of money, then maybe it would stop its programs or at a minimum come to the negotiating table.

But Trump’s theory was proven wrong, and it shouldn’t have been a surprise.

“The US never had a chance to get Beijing to substitute America’s national interest for its own," Rapp-Hooper said.

So Trump lashed out using his favorite weapon, Twitter. This was from July 29.

I am very disappointed in China. Our foolish past leaders have allowed them to make hundreds of billions of dollars a year in trade, yet... — Donald J. Trump (@realDonaldTrump) July 29, 2017

...they do NOTHING for us with North Korea, just talk. We will no longer allow this to continue. China could easily solve this problem! — Donald J. Trump (@realDonaldTrump) July 29, 2017

The core issue is Washington’s primary fear that North Korea develops means of reliably firing nuclear missiles capable of reaching the US. China’s primary concern is very different. It’s terrified that the Kim regime could collapse, sending millions of North Korean refugees flocking into China.

That’s something Beijing expressly does not want. Beijing prioritizes stability on the Korean Peninsula. Any change, China fears, may lead to problems for the Chinese government down the road.

Plus, if America won a war with North Korea, it might be able to negotiate the reunification of the peninsula on its, and South Korea’s, terms. That wouldn’t only be politically bad for China, but also US and South Korean forces would be stationed on China’s border — something Beijing doesn’t want.

There’s yet another benefit for China to let things continue as they are. "The Chinese have an incentive to let this fester because it's a big distraction for Washington," said Narang. “North Korea is a huge thorn in our side.”

In essence, keeping American eyes on North Korea allows China to continue to do what it wants in the region, like build military facilities on artificial islands it constructed in the South China Sea.

It’s worth remembering through all of this that Trump thought China could easily solve the North Korean problem. Then after a 10-minute conversation with Chinese leader Xi Jinping in April, he realized it was more complicated than he thought. Now Trump has changed his mind again and thinks China didn’t do enough to stop North Korea.

So the Trump administration slapped sanctions on China on June 29, as my Vox colleague Zeeshan Aleem noted at the time.

“While we will continue to seek international cooperation on North Korea, the United States is sending an emphatic message across the globe that we will not hesitate to take action against persons, companies, and financial institutions who enable this regime,” Treasury Secretary Steve Mnuchin said in a June 29 statement on the earlier round of sanctions, clearly alluding to China.

The administration is thinking of taking additional punitive measures against Beijing, reports Politico. Those could include new trade restrictions or sanctions. Either way, whatever Trump chooses to do is unlikely to work, according to Zachary Keck, an Asia security expert at the Nonproliferation Policy Education Center.

“Placing sanctions on China is unlikely to have much success,” he told me in an interview. “Ultimately, Chinese leaders' calculus — that living with a stable if nuclear-armed North Korea is better than living with millions of refugees flooding into their country — won’t change.”

The costs would have to be very, very high to change the way China views the North Korea situation. And it’s unlikely the US can inflict that much damage without hurting its own economy as well.

Also, Congress went further last week, overwhelmingly passing legislation slapping even more punitive sanctions on Pyongyang (as well as on Iran and, most notably, Russia); the White House said Trump will sign the bill soon. It’s a good course of action to take, Rapp-Hooper noted, saying there was some success getting North Korea to the negotiating table in the 1990s — even if it might not work now.

After all, now that the country has what it wants — an ICBM — it’s hard to know what sanctioning Pyongyang might do other than slowing down the program, Narang told me.

It’s no surprise that Trump is lashing out at China on Twitter, since Beijing was so central to his strategy for containing North Korea and China clearly didn’t want to move as far as he wanted it to. It remains to be seen if his next plan — squeezing China and North Korea simultaneously — works any better.

There are no good options for Trump

It might seem that this weekend’s events were particularly troubling. But the truth is the US and North Korea have been going at it like this for decades now. The question is what can Trump do about it? Sadly, not much.

Trump has three bad options. He could try to take out North Korea’s nuclear facilities with a “surgical strike,” but that risks North Korea retaliating by attacking South Korea and Japan. He could try diplomacy, but that has not historically worked. “After almost 25 years, we should be completely disabused of any thought that there is a rational bargain to be had with North Korea that will be honored by North Korea,” Gregson told me.

And then there are the sanctions — which Trump is trying. But many items the country wants and needs, like weapons and fuel, are already highly sanctioned by the US. North Korea hasn’t yet changed its course.

So no matter what Trump does, there is a downside. That’s scary. But the really scary thing is if the North Korea situation doesn’t get solved, perhaps a similar series of events could happen again in the future. And, next time, it might get worse.