Along with the loss in political standing has come a decline in economic power. U.S. direct investment in Latin America slid from 30 percent to 20 percent of the total from 1998 to 2007, according to the U.N. Economic Commission on Latin American and the Caribbean.

The U.S. still does $560 billion in trade with Latin America, but in the meantime other countries are muscling in. China's trade with Latin America jumped from $10 billion in 2000 to $102.6 billion last year. In May, a state-owned Chinese company agreed to buy a Peruvian copper mine for $2.1 billion.

Other countries are also biting into U.S. military sales in the region. Boeing Co. is vying with finalists from France and Sweden for the sale of 36 jet fighters to Brazil. Venezuela's Chavez has committed to buying more than $4 billion in Russian arms, from Sukhoi jet fighters to Kalashnikov assault rifles.

In April, Brazil and Russia agreed to jointly design top-line jet fighters and satellite-launch vehicles, and Brazil is getting technology from France to build a submarine.

"Similar deals could have been made with the United States had it been willing to share its technology," said Geraldo Cavagnari, of the University of Campinas near Sao Paulo.

Last month, Russian Prime Minister Vladimir Putin offered to help Chavez develop nuclear power. Even Colombia, the staunchest U.S. ally in South America, isn't limiting its options. After expressing alarm about the Russian warships a week ago, its defense minister, Juan Manuel Santos, promptly headed for Russia himself to discuss "better relations in defense." Chavez says he expects to hold joint Russian-Venezuelan naval exercises as early as November.

Bolivia also is looking to deepen ties with Russia and Iran.

Although the Islamic republic's ambassador has yet to arrive in South America's poorest country, its top diplomat there announced Friday that Iran will open two low-cost public health clinics.

And while Bolivia's only announced Russian hardware purchase is five helicopters for civil defense, Moscow's ambassador told the AP — after Bolivia booted the U.S. ambassador — that Russia has every right to help Latin American nations arm themselves.

"We know of many historical cases of U.S. intervention in Latin American countries," said the diplomat, Leonid Golubev.

Thomas Shannon, U.S. assistant secretary of state for the hemisphere, wouldn't comment directly on whether the U.S. has lost influence in Latin America. But he added that there is no doubt that the U.S. still holds most of the military power in the Caribbean, and said it has no interest in reviving "Cold War rhetoric." Shannon also noted that overall U.S. aid to the region will reach $2.2 billion for 2009, to total more than $14 billion during Bush's presidency.