Here’s what Trump is trying to achieve by tweeting about China-North Korea trade

In a shift in Twitter strategy, President Donald Trump attacked the Chinese on Wednesday for continuing to trade with North Korea.

This tweet is the latest example of Trump pressuring China to use its economic relationship with North Korea to end the isolated country’s nuclear weapons program. China has long been North Korea’s biggest trading partner and a key importer of the isolated country’s primary export, coal. In May, the New York Times reported that China accounts for more than 80% of North Korea’s trade.

The president’s tweet comes two days after North Korea tested an intercontinental ballistic missile allegedly capable of striking the United States. It’s unclear whether Kim Jong Un, North Korea’s supreme leader, is able to mount a nuclear warhead on the missile. Nonetheless, the threat has the world on alert.

For months, Trump has tweeted about the Chinese and North Korean economic relationship. He has repeatedly called on China to leverage its trade relationship with North Korea to make the American foe end its nuclear weapon program. Trump has specifically noted negotiations with Chinese President Xi Jinping in an attempt to publicly push the Chinese to alter North Korea’s posture.

If trade between China and North Korea did grow earlier in 2017, it would mesh with a Washington Post report in May that China has continued to quietly import coal from North Korea and maintain its key economic relationship with the American foe.

It would also signal the Chinese lied to the rest of the world. In February, less than a month after Trump’s inauguration, China said it would stop importing North Korean coal. In April, China reportedly turned away North Korean barges laden with coal.

Trump, however, may be cherry-picking data that fits his narrative to apply public pressure on China ahead ahead of the G20 Summit in Germany taking place on Friday and Saturday.

While Chinese trade with North Korea did grow 37.4% in the first quarter of 2017 over the same period in 2016, those numbers don’t account for the entire period impacted by the Chinese coal embargo. According to the Chinese government, imports of North Korean goods to China fell by 30% in May.

Attacking China’s trade with North Korea, while potentially politically effective, also misses the question of how North Korea has been able to function despite sanctions. China has long helped North Korea find loopholes in sanctions and avoid international financial crackdowns by employing fraudulent labeling and forcing North Koreans working overseas to send money home, the Times reported in May.

But even if that 30% drop is real, China still trades with North Korea far more than it did as recently as 2010. Trade between China and North Korea nearly doubled between 2010 and 2014. Between 2002 — when former President George W. Bush dubbed North Korea a member state of the “Axis of Evil” — and 2015, trade between China and North Korea increased more than 500%.

A drop in trade between China and North Korea could hurt the cashflow of the isolated country’s government, but it would have to shrink precipitously to go back to the levels it was before Barack Obama’s presidency.