The Dow closed down 459 points Monday, showing how skittish investors are about President Trump’s attacks on Amazon as well as a potential trade war between the United States and China. And for good reason. Presidents usually don’t pick on individual companies, and trade wars aren’t generally good for business, hence the name.

Mr. Trump and the rest of the world have had some provocation for their anti-China moves. For years, many analysts agree, China has manipulated its currency, subsidized state-owned enterprises, and used various schemes to keep foreign companies out unless they hand over their technology. A free market requires rules. When a nation the size of China bends them, you can’t send it to its room. Options are limited.

Yet there’s also another vision of tariffs and trade wars – a protectionist view. The hope is that they can boost a domestic economy. In limited cases, that can be true. But the concept misses one of the most categorical points in the history of human progress. Our prosperity depends on each other. Not as Americans. As people.

Wealth is not finite. It grows. And it has grown fastest as the world’s capacity to connect and collaborate has grown. The answer to any economic stagnation is always, How can we work better together? The bigger the “we,” the greater the potential. That doesn’t mean governments have always managed that growth well or fairly. But, as investors know well, that also doesn’t mean closing a country’s front door.

Here are our five stories for today, including a question of conscience in Yemen, a one-word look into the Russian soul, and a group of South African grandmothers you really don't want to mess with.