In simple words, It stemmed from the annexation of the Republic of Texas by the U.S. in 1845 and from a dispute over whether Texas ended at the Nueces River (the Mexican claim) or the Rio Grande (the U.S. claim).
The conflict, which was repeatedly won by US forces, resulted in the US acquiring upwards of 500,000 sq kilometers of Mexican land extension of time from the Rio Grande to something like the Pacific Ocean.
The biggest challenges faced by the Jewish settlers who arrived in
Israel
beginning in the 1880s was introducing modern agricultural methods
to an
ancient culture.
Mosquito-borne disease in the wetlands represented another
challenge.
