As Congress and the Trump administration debate immigration reforms with important legal and social implications, they must not lose sight of an overarching truth: Robust immigration levels are vital to growing the American economy.

Legislators of both parties, policy makers and families all want faster economic growth because it produces more resources to fund national priorities and raise living standards. But growth since the end of the Great Recession has been frustratingly slow, averaging only 2.2% net of inflation, down...