There’s no doubt that a spending hawk such as Lee, who has proposed a balanced-budget amendment in the past, knows that. Yet at the heart of his and Marco Rubio’s plan is a massive giveaway to parents in the form of a new $2,500 child tax credit (this would be added to an already existing $1,000 child credit) with no phase-out due to income.  However, because it’s “limited to the sum of total income and payroll tax liabilities, including employer-side payroll tax liability,” it means that low-income parents won’t be able to claim the full amount.

The expanded child credit is a big reason why, as AEI’s Pethokoukis grants, the plan would “lose something like $4 trillion in federal tax revenue over a decade, maybe half that if you apply ‘dynamic scoring’ that factors in the effects of economic growth.” (Dynamic scoring attempts to model changes in people’s behavior to changes in the tax code. While the method is easily abused, its core insight—that we change our consumption patterns when costs and benefits vary—is sound.)

But unlike cutting taxes on business activity or trimming top marginal tax rates, expanding the child tax credit has nothing to do with spurring economic growth.