<P> Border disputes continued . The U.S.'s desire to expand its territory continued unabated and Mexico's economic problems persisted, leading to the controversial Gadsden Purchase in 1854 and William Walker's Republic of Lower California filibustering incident in that same year . The Channel Islands of California and Farallon Islands are not mentioned in the Treaty . </P> <P> The border was routinely crossed by the armed forces of both countries . Mexican and Confederate troops often clashed during the American Civil War, and the U.S. crossed the border during the war of French intervention in Mexico . In March 1916 Pancho Villa led a raid on the U.S. border town of Columbus, New Mexico, which was followed by the Pershing expedition . The shifting of the Rio Grande would much later cause a dispute over the boundary between purchase lands and those of the state of Texas, called the Country Club Dispute . Controversy over community land grant claims in New Mexico persists to this day . </P> <P> Disputes about whether to make all this new territory into free states or slave - holding states contributed heavily to the rise in North - South tensions that led to the American Civil War just over a decade later . The treaty was leaked to John Nugent before the U.S. Senate could approve it . Nugent published his article in the New York Herald and, afterward, was questioned by Senators . Nugent did not reveal his source . </P> <P> The Treaty of Guadalupe Hidalgo led to the establishment in 1889 of the International Boundary and Water Commission to maintain the border, and pursuant to newer treaties to allocate river waters between the two nations, and to provide for flood control and water sanitation . Once viewed as a model of international cooperation, in recent decades the IBWC has been heavily criticized as an institutional anachronism, by - passed by modern social, environmental and political issues . </P>

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