US population is growing for a combination of immigration and just slightly better birth rates than others. It's nowhere close to above-replacement levels (2.1). Just check out the population pyramid, and you can see there are less younger kids than older ones.
And almost all growth is immigration, the fertility rate hits new lows constantly.
https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2024/...
“U.S. Fertility Rate Drops to Another Historic Low”
I'm increasingly convinced that the goal is to balkanize the US and establish a Network State guided by silicon valley, as described by Curtis Yarvin
The problem has not been solved, and all western governments are hoping to delay the problem through immigration. This buys them time to see what solution Japan, SK and China can come up with, and copy that instead of taking risks with potentially abysmal results.
Second of all, majority of US population is urban. People in NY or Bay Area can't elect a president who represents their interests due to how Electoral College is designed but attempting to change their opinions on having children by banning porn is a pipe dream.