I believe OP is referring to how immigration is the only known working solution to a decreasing population.
The US fertility rate is already 1.6 births per woman[0], and the population is only not decreasing because it still receives far more immigration than, say, Japan or South Korea.
The US fertility rate is already 1.6 births per woman[0], and the population is only not decreasing because it still receives far more immigration than, say, Japan or South Korea.
[0]: https://www.cdc.gov/nchs/data/vsrr/vsrr038.pdf