For more info, see;
http://apstudent.com/ushistory/docs1801/guadelup.htm
Treaty of Guadelupe Hidalgo
Treaty between the U.S. and Mexico
February 2, 1848
TREATY OF PEACE, FRIENDSHIP, LIMITS, AND SETTLEMENT BETWEEN THE UNITED STATES OF AMERICA AND THE UNITED MEXICAN STATES
Concluded at Guadalupe Hidalgo, February 2, 1848; Ratification Advised by Senate, with Amendments, March 10, 1848; Ratified by President, March 16, 1848; Ratifications Exchanged at Queretaro, May 30, 1848; Proclaimed, July 4, 1848.....(See link for more.)
Sorry Mexico. We bought it, its ours.
Well, they've all been "working real hard" and have plenty of money saved up. We could sell it back to them.
How much, including inflation, capital improvements and "whatever the market will bear", do you think we should be asking for SoCal?