We Can Prevent a Great Depression. It’ll Take $10 Trillion.

Don’t think of that number as “big” or “bold.” Just think of it as the appropriate dosage for a once-in-a-century economic affliction.

Last week, House Democrats unveiled their latest pandemic-relief package. The bill combines aid for families, a bailout for struggling cities and states, and additional funds for testing, tracing, and hospitals. The price tag is about $3 trillion—and it comes just weeks after the president signed an economic-relief package worth about $2 trillion.

Republicans have assailed the bill as a profligate wish list. Even Americans who are suffering from...