But even with the demise of the Libyan dictator, plus Osama bin Laden, Iraq's Saddam Hussein and Serbia's Slobodan Milosevic, there are still autocrats around the world hostile to the U.S., notably in Cuba, Venezuela, North Korea and Iran.
America's most determined foes have been bucking more than just the world's sole surviving superpower, which spends as much on its military as all other countries combined. All faced social and technological trends that made their work more difficult by opening more borders to trade and travel, promoting ethnic and religious tolerance and wiring the world for high-speed Internet.
But as long as the U.S. maintains its leadership role in world affairs, it will find itself a tempting target. Among the despots and autocratic regimes hostile to the U.S. are:
—Cuban leader Fidel Castro, who survived CIA assassination plots, the Bay of Pigs invasion and the U.S. economic embargo to excoriate and antagonize the United States for more than half a century. Castro, 85, formally resigned as president in February 2008 due to illness but handed the reins to his brother, Raul, and the revolutionary regime survives. Cuban-U.S. trade is minimal and there are no diplomatic relations between the two countries. The U.S. accuses the Cuban government of trampling on human rights and silencing dissent, while Havana portrays itself as a victim of U.S. bullying.
—Venezuelan President Hugo Chavez, a left-wing activist and former military officer who came to power in 1999 and instituted radical changes in economic and social policy, including nationalization of the oil industry. Chavez has accused Washington of plotting to invade Venezuela, called for containment of the U.S., aligned himself with Cuba and signed major arms deals with Russia to build Venezuela into a regional power. The U.S. likes to portray Venezuela as more of an irritant than an adversary, but that could change if Chavez adopts more aggressive policies.
— Kim Jong Il of North Korea, a Stanlinist-style nation with a 1 million-man army that has been a thorn in the side of the U.S. since the Korean War. In recent years the U.S. has sought to persuade Kim to give up his small nuclear weapons program, offering economic aid and diplomatic favors as a bargaining chip. But the U.S. accuses Kim of repeatedly reneging on promises to disarm while selling weapons expertise abroad. The U.S. and other nations accused Pyongyang last year of torpedoing a South Korean navy ship and shelling a South Korean island. With the North Korean leader believed to be gravely ill, the key to Washington's future relations with Pyongyang may be Kim's son and heir apparent, Kim Jong Un.
—Iran clerical leadership. The theocratic regime in Tehran has demonstrated little tolerance for dissent and a deep and abiding hostility to Washington since the overthrow of the U.S.-backed regime of the shah of Iran in 1979. President Mahmoud Ahmadinejad's broadsides against the U.S. and Israel are a regular feature of U.N. General Assembly meetings, but his is just one voice among many in the Iranian government, which Western analysts say consists of a jigsaw puzzle of anti-Western factions.
The present conflict with Washington grows out of concerns about Iran's support for terror groups in the Middle East and attacks against U.S. troops in Iraq and Afghanistan, but mainly focuses on Tehran's nuclear ambitions. The U.S. says Iran is laying the groundwork for a nuclear weapons program that could threaten the Middle East, U.S. and Europe. Iran says it is interested only in peaceful nuclear technology.
Not all dictators are regarded as enemies of the U.S.; during the Cold War and beyond, many have been treated as stalwart allies. Today, a number of autocrats endure criticism from the U.S. but are thought to represent little threat to Washington's strategic interests, including President Aleksander Lukashenko of Belarus, Robert Mugabe of Zimbabwe, Omar al-Bashir of Sudan and Islam Karimov of Uzbekistan.
From the U.S. perspective, the survival of openly hostile despotic regimes may be less important than the rise of rival economic and political powerhouses like China, India, Brazil and Russia, a trend that some experts say could one day create a world where the United States becomes one major power among many competing for influence and markets.
The decline and fall of Qaddafi, Saddam and others doesn't mean the age of hostile dictatorships is ending. Just as enemies can become allies, allies can become adversaries.
The U.S. considered Saddam a check on the power of the clerical regime in Iran until his invasion of Kuwait led to a deadly U.S. war in 1991. After the 2003 U.S.-led invasion of Iraq, Saddam became the ace of spades in the U.S. military's deck of cards representing its most-wanted list.
He ultimately was cornered by U.S. forces in a hole near his hometown of Tikrit and executed by the new Iraqi government in 2006.
Today the U.S. faces the challenge of helping prevent newly liberated countries from slipping back into authoritarianism. While Taliban leader Mullah Omar was driven from power in Afghanistan in 2001, his movement made an impressive comeback and could once again become a major force in Afghanistan politics as the U.S. withdraws.
Qaddafi's death Thursday is just the beginning of a critical new phase in Libya's history, said Anthony Cordesman of the Center for Strategic and International Studies in Washington. The leaders of the Libyan rebellion inherit a divided population, a ruined economy and a barely functioning state — all crippled by decades of Qaddafi's erratic rule.
"He left Libya with a unique set of problems," Cordesman said. "You'd have to go back to Nero or Caligula to find someone who was able to impose their own personal eccentricities on a state to the degree that Qaddafi did."