Santos, 58, easily bested his challenger, former Bogota Mayor Antanas Mockus. With 98% of votes counted, Santos had garnered 69% of the votes in the runoff election to his challenger's 25%. He will be inaugurated on Aug. 7.

Santos, who also outpolled Mockus in last month's first-round election, had been heavily favored to win after he had gained the backing of several major political factions, including third-place finisher German Vargas Lleras. To top it off, the Colombian military recently rescued four armed forces hostages long held by leftist guerrillas, an event seen as boosting Santos' bid.

Meanwhile, Mockus fared poorly in the final presidential debate and failed to forge an alliance with the Polo Democratico, Colombia's largest opposition party.

"Security is still an issue here and Santos was able to sell himself as the clearest representative of [current President Alvaro] Uribe and his legacy," said Marcela Prieto, director of the Political Science Institute of Colombia. "Mockus was not able to elevate his campaign appeal as he had to do. He made mistake after mistake."

Santos is expected to continue Uribe's good relations with the United States, which regards Colombia's current leader as its chief Latin American ally and which over the last decade has delivered more than $6 billion in military and development aid to help the country fight drugs and terrorism.

The victory culminates lifelong presidential ambitions for Santos, who previously had served in ministerial positions under three presidents but never stood for election. After Uribe in February finally was barred from running for a third term by a court decision, Santos quickly emerged as the leader of the Uribista coalition of parties. His great uncle Eduardo also served as president and founded the El Tiempo newspaper, the country's most important.

Colombia's usually low voter turnout, exacerbated by poor Sunday morning weather in the capital, Bogota, and two televised key World Cup soccer matches, didn't help Mockus, also 58, to pull off a surprise.

"I came to vote to vote for Santos and assure that what Uribe has done won't be lost," said Alejandro Zambrano, 33, before voting in a convention center in central Bogota

Criticized in the past for overt machinations and for having changed parties, Santos gained national visibility as Uribe's defense minister. In that post he oversaw the continued improvement of the armed forces, which have seized the battlefield initiative in the decades-long battle against the leftist Revolutionary Armed Forces of Colombia, or FARC.

Santos also helped direct the spectacular rescue of 15 hostages, including three U.S. defense contractors and a presidential candidate, from rebel clutches in July 2008.

But he also directed the armed forces' daring incursion into Ecuadorean territory to kill FARC leader Raul Reyes in March 2008, a breach of sovereignty that escalated tensions with Colombia's neighbors. And he had to overcome a scandal that occurred while he was defense minister in which scores of civilians were killed by troops who then claimed them as rebel casualties.

Although Santos, who studied at the University of Kansas and Harvard University, enters office with a solid majority in both congressional houses, he faces a difficult array of issues. The pension and health insurance systems are both headed for insolvency, analysts warn, while the poverty and unemployment rates remain among the highest in Latin America. Santos must also "reestablish good relations with our neighbors," Prieto said.

Though Mockus' expressed willingness to raise taxes may have hurt him with voters, many observers expect that Santos eventually will have to institute tax increases to stem the red ink.

**Kraul is a special correspondent.