Supporters blandly describe their plan as “Child Tax Credit improvements for 2021.” It would replace today’s annual child tax credit, which tops out at $2,000, with more-generous “child allowances,” payable monthly. Those allowances are federal payments of $3,600 (or $300 a month) for each child under 6 and $3,000 ($250 a month) for older children. The current credit increases with income from work; the new one would provide the same large payments to all.