I've always thought that might be the real motivation behind all the government open-border policies, but no politician wants to admit it.
Actually, Lindsey Graham as much as admitted it in one of the undercard debates. He talked about it in terms of needing the immigrants to pay for the Social Security system, etc.
Now if the prevailing culture for the last 50 years or so hadn’t promoted a radical feminist agenda that discourages reproduction (abortion, pursuit of career over family, etc.), as well as population control hysteria, we wouldn’t have this problem.