Mexican President Felipe Calderon, elected last year, has sent thousands of troops and police into drug strongholds in a crackdown on his nation’s drug cartels.

But Mexican drug lords are powerful, wealthy and have deep connections to police and public officials. No one knows whether Calderon’s crackdown will work.

“The jury is still out, because other Mexican presidents early on in their terms made similar gestures. Then they backed off,” said Michael Scardaville, a USC associate professor of history specializing in Mexico.

Mexico, a nation of 107 million, is the main exporter of cocaine, marijuana and methamphetamines to the United States. It is also a major exporter of heroin to the U.S., according to the Central Intelligence Agency’s World Fact Book on Mexico.

Events last month illustrated the size and scope of the Mexican drug business:

• On March 18, the U.S. Coast Guard seized 21 tons of cocaine on a ship in the Pacific Ocean off Panama that was bound for Mexico. The seized cocaine was worth an estimated $300 million.

• Mexican and U.S. Drug Enforcement Administration officers seized $205 million at a Mexico City house. The money belonged to people who sold chemicals to drug groups that manufacture methamphetamines, according to the DEA.

Drugs and drug smuggling became entrenched in Mexico in the 1980s, when the country underwent a depression that threw millions out of work.

Not only was there “significant out-migration from Mexico to the U.S. as a survival strategy,” but also a small minority of Mexicans went into the drug business as a way to make money, Scardaville said. The porous border allowed Mexico to become the United States’ primary provider.

The huge U.S. market didn’t hurt either, Scardaville said.

In fact, he said, one well-known cartoon portrays Uncle Sam pointing at Latin Americans and saying, “Drug Traffickers.” The Latin Americans, meanwhile, are pointing at Uncle Sam and saying, “Drug Addict.”

Drug-related violence is a fact of life in Mexico, especially along the U.S. border, where murder, gun battles and kidnappings are frequent, according to U.S. State Department travel advisories.