The financial markets are the only thing that can stop Trump’s reign of chaos.

When the New York Stock Exchange opens on Monday at 9:30 a.m. we will see just how seriously the world takes the assault Elon Musk and Donald Trump launched on the American system of government.

What follows is a guide for interpreting the drop.

First, some ground rules. The securities markets have a system of circuit breakers to halt massive declines. There are three circuit breakers that are measured by calculating a percentage decline in the S&P 500 from the close of the previous day: Level 1 (7 percent), Level 2 (13 percent), and Level 3 (20 percent). If Levels 1 or 2 are tripped before 3:25 p.m., all trading is halted for 15 minutes. If Level 3 is tripped at any point in the day, trading is halted for the remainder of the day.