Why is it most effective, can you give a price estimate? The USSR had the longest and very well defended border with 230 thousand strong border guard. Let's say the US, with a much shorter border needs as many troops just to be sure. At this time the CBP has 62k troops and 18.2B budget. So for 47B more we could get the stronger border guard than the USSR to guard a shorter border than the USSR. Meanwhile, we spent 47B on average in pure foreign aid in 2013-2018, not counting indirect spending through trade agreements and such and still get hundreds of thousands foreigners crossing illegally every month. I don't see how the money spent on foreign aid are effective at all.
https://www.forbes.com/sites/adamandrzejewski/2021/08/04/new...
https://en.m.wikipedia.org/wiki/U.S._Customs_and_Border_Prot...
https://en.m.wikipedia.org/wiki/Soviet_Border_Troops