Grant Wahl explains why the USA-Mexico soccer rivarly is so unique and important -- and what a shame it is that a new format would prevent a meeting of the neighbors for this region's World Cup qualifying. The new format has already been approved by Concacaf, the USA and Mexico, and awaits FIFA's approval.

"Over the past 15 years, U.S.-Mexico has turned into the greatest international sports rivalry in North America, a spectacle that has transcended soccer and helped grow the U.S. national team's popularity among mainstream American sports fans," writes Wahl. "The two U.S.-Mexico World Cup qualifiers that take place every four years -- one in the U.S., usually Columbus, Ohio, the other in Mexico City -- have filled stadiums with rabid supporters from both countries and turned into must-see TV."

So why change the qualifying format? It comes down, as you might expect, to politics. The new qualifying format would be good for the Caribbean island nations, who will get at least six World Cup qualifiers. Most of the Caribbean countries got only two World Cup qualifying games before they were eliminated.

FIFA's has a one-country, one-vote policy when it comes to elections. The 35-member Concacaf includes 23 Caribbean island nations whose ability to band together as a voting bloc (under Concacaf president Jack Warner of Trinidad & Tobago) gives them power in the FIFA boardroom that far exceeds their impact on the soccer field.