There have been several comments made here about Mexico taking over other countries once they get in control of U.S. If they have to actually fight a war to take over other countries, this is what they have to work with.
http://en.wikipedia.org/wiki/Mexican_Armed_Forces
For comparison, the U.S. has the largest defense budget in the world; FY2010 base budget of 533.8 billion with an additional 130 billion request to fund the War On Terrorism. The U.S. has 1,137,568 on active duty within the U.S. and 848,000 in reserves. I believe the article said 1,421,668 on active duty worldwide. They will be increasing those numbers soon because of the War On Terrorism.
See http://en.wikipedia.org/wiki/United_States_armed_forces
Of course, we will probably never again fight a war with Mexico, but it is interesting to look at the statistics.
Most wars in Mexico have been of internal nature, or imposed upon Mexico by foreign powers, such as the United States and France. The only notable exception was on WW2, when Mexico fought for the Allies against Japanese forces on the Pacific.
•Mexican War of Independence (1810-1821)
•Central American Federation War of independence (1822-1823)
•Texas War of Independence (1835-1836)
•First Franco-Mexican War ("The Pastry War") (1838)
•Yucatan Secession (1839-1843)
•Mexican-American War (1846-1847)
•Yucatan Rebellion (1847)
•Second Franco-Mexican War (1862-1867)
•Yaqui Indian War (1899-1904)
•Mexican Revolution (1910-1922)
•US Occupation of Veracruz (1914)
•US Punitive Expedition (1916-1917)
•World War Two (1942-1945)
•Chiapas Uprising (1994-Present)
•EPR Marxist Guerrilla Conflict (1996-Present)
•Mexico's Drug War (2006-Present)
The last three are ongoing, low-intensity conflicts, meaning no outright war between the opposing parties has ever happened, but it doesn't mean casualties don't exist. For instance, since the Mexico's Drug War was proclaimed by Mexican President Felipe Calderon Hinojosa on December 11, 2006, more than 18,000 people have been killed by confrontations between federal, state and local police forces against drug cartel members.
Ugh - I think maybe I should have posted this in the "Off Topic" Threads. If so, I apologize.