If we stopped spending billions on pop con, and instead helped them improve infrastructure, agriculture, education, and free markets, then the problem would be solved.
All industrialized countries reach an equilibrium in which the education and the type of employment a modernized economy entails naturally leads to reduced fertility/family size.
It has been seen in every western country, even prior to the widespread availability of effective contraception.
The solution is not 1 through 3 noted above, its helping them get infrastructure, agriculture, education, and free markets.
There is simply no way to keep a country living in third world poverty and honestly expect their family size to shrink without industrialization.
Why do they need help, while we "did it on our own."?
Because we had land for expansion, as well as our own strategic resources, when our country grew.
Our european immigrant ancestors enjoyed something these third world folks don't:
A place to move to where there was still land anbd jobs to be had.
That and the fact that we now control third world resources so that they are unable to take advantage of their own resources.
You either help them attain what we have, or expect continued warfare and terrorism.
Remember, in capitalism, the pie doesn't stay the same size.
Bringing third world countries up to first world standards does not take anything away from the first world in the long run, because it opens more markets for our own economy, especially when you consider that economies cannot continue to expand with contracting population bases.
The best way to lose an enemy is make them your friend.
Replace demographic warfare with capitalism and investment, and you will have a far greater return on your money.
And at least the possibility of peace with them.
Continue demographic warfare....expect terrorism and warfare for the foreseeable future.