U.S. Invading Mexico?

Iraq. Afghanistan. Pakistan. Libya. Yemen. Somalia. Uganda. Mexico? Countries where the United States have sent soldiers and police to arrest or kill thugs.
From the New York Times: American law enforcement agencies have significantly built up networks of Mexican informants that have allowed them to secretly infiltrate some of that country’s most powerful and dangerous criminal organizations, according to security officials on both sides of the border.
As the United States has opened new law enforcement and intelligence outposts across Mexico in recent years, Washington’s networks of informants have grown there as well, current and former officials said. They have helped Mexican authorities capture or kill about two dozen high-ranking and midlevel drug traffickers, and sometimes have given American counternarcotics agents access to the top leaders of the cartels they are trying to dismantle.
Typically, the officials said, Mexico is kept in the dark about the United States’ contacts with its most secret informants — including Mexican law enforcement officers, elected officials and cartel operatives — partly because of concerns about corruption among the Mexican police, and partly because of laws prohibiting American security forces from operating on Mexican soil.
“The Mexicans sort of roll their eyes and say we know it’s happening, even though it’s not supposed to be happening,” said Eric L. Olson, an expert on Mexican security matters at the Woodrow Wilson Center.
“That’s what makes this so hard,” he said. “The United States is using tools in a country where officials are still uncomfortable with those tools.” http://www.nytimes.com/2011/10/25/world/americas/united-states-infiltrating-criminal-groups-across-mexico.html?_r=1
Can you imagine the outrage in the United States if we let the Mexican, Canadian, Russia or any other country's police department or military to operate in the United States?
Then we wonder why the United States are considered to be bullies of the world.