RUTHFULLY YOURS

Conventional wisdom says that Pyongyang already faces extreme economic and diplomatic pressure. But in reality the United Nations and U.S. only began to impose broad sanctions last year, and even U.S. allies such as Singapore and Thailand have been slow to enforce them. China and Russia continue to support the Kim regime—China through oil exports and other commerce, and Russia through payments for North Korean slave labor.

Shutting down those lifelines should be a top priority. After the North’s intermediate-range missile launch in September, the U.S. circulated a draft resolution at the United Nations Security Council to do just that. But Russia and China resisted and the U.S. caved; Resolution 2375 only capped oil exports and labor contracts. The Trump Administration portrayed the unanimous vote at the U.N. as a victory, but the resolution kept open many of Pyongyang’s cash lifelines.

The U.S. even rewarded Beijing for the vote by pausing the process of sanctioning Chinese companies that violate sanctions. That pause ended last week when the Treasury Department put four companies based in the Chinese city of Dandong on its financial blacklist. Treasury is playing catch-up with a June report on sanctions-busting firms by the private research group C4ADS. The U.S. government continues to hold back on other “secondary sanctions,” especially against Chinese banks, for fear of losing Beijing’s cooperation.

But China’s internal enforcement of sanctions is patchy. Chinese banks froze the accounts of some North Korean customers while continuing to finance Chinese companies that are breaking sanctions rules. Imports of coal from North Korea have continued in violation of a U.N. resolution in August that banned all trade in North Korean coal. The Trump Administration can make an example of these firms and expose Beijing’s failure to honor its sanctions promises.

The U.S. response to Wednesday’s missile tests should also include security measures. The redeployment of tactical nuclear weapons to South Korea is needed to deter a nuclear attack from the North. Showing Pyongyang that American forces would retaliate overwhelmingly to an attack on a U.S. ally, even at the risk of an ICBM attack on the U.S. mainland, would help prevent Kim miscalculating.

The deployment of more Thaad missile-defense radars and launchers to South Korea would send a strong signal to China that its support for Pyongyang has consequences. At the end of last month Beijing bullied South Korean President Moon Jae-in into freezing deployment of the Terminal High-Altitude Air Defense system. But the U.S. should insist it needs new Thaad units to defend its own forces and deter attacks from the North.

The U.S. and South Korea can also expand their programs to encourage North Koreans to defect. The Kim regime’s former Deputy Ambassador to the U.K. Thae Yong-ho has good ideas on how to do this. Mr. Thae, who fled to freedom in the South last year, testified to Congress last month on human-rights messages that will resonate in the North.

The soldier who defected across the Demilitarized Zone on Nov. 13 seems to have been inspired by watching and listening to South Korean media. If China accepted refugees across its North Korean border and sent them to the South, word would spread in the North and internal instability might grow. Regime change assisted by China is the best way to end the North Korean threat short of war.

The Trump Administration has done more than its predecessors to thwart North Korea’s nuclear progress, but it is still far from using maximum pressure. It may not work in the end, but the alternatives are terrible: acquiescence or war. Wednesday’s ICBM test shows Kim is getting close to his goal of threatening American cities, so why is the U.S. not using all the tools it has to stop him?