Joe boetchcr, age 14, of Marion, Onlo, for his question:

WHAT WAS THE TACNA ARICA DISPUTE?

  Tacna Arica Dispute was a long standing argument or debate   between Peru and Chile over the provinces of Tacna and Arica,   which before the War of the Pacific had betonged to Peru.   The Treaty of Ancon, ending the war, provided that the   provinces remain in Chile's possession for 10 years, after which a plebiscite would be held to decide their ultimate   disposition.

Ten years later Peru amended the execution of the treaty,   but on the understanding that only Peruvian citizens be   allowed to vote. No agreement could be reached in the matter   and the dispute lingered. 

In 1912 representatives of both nations nominated the   president of the United States to arbitrate the dispute.   President Calvin Coolidge rules in 1925 that a plebiscite be   held, but the decision was abandoned because of riots in the  provinces.

In 1928 d treaty was finally arranged and subsequently   ratified in 1929. It gave Tacna to Peru and Arica to Chile,  the latter agreeing to pay Peru an indemnity of $6 million.