This country's next president will be the man who can solve a riddle worthy of the Sphinx: How does the candidate of an entrenched political party win the support of voters whose first choice was an independent running against machine politics?
If either Horacio Serpa or Andres Pastrana can answer that question, he may win the 2.8 million votes cast for Noemi Sanin, the third-place candidate in Sunday's first-round balloting. Or at least enough of those votes to become president.
Sanin is out of the race, but her supporters will be the deciding factor in the June 21 runoff. "These definitely are the votes that are going to elect the president," wrote columnist Francisco Santos in El Tiempo, the country's largest-circulation daily newspaper.
Liberal Party member Serpa and Pastrana, candidate of the Conservative Party, finished Sunday's balloting in a virtual tie. The difference between them was less than 0.25% of the 11 million votes cast.
Each began courting Sanin's supporters after she rebuffed them both, refusing the role of kingmaker.
"I would be wrong to tell the millions of Colombians who voted for me how to vote in the second round, because their nature is independence," she told the crowd gathered at her election night party. "It is my obligation to respect that liberty."
Sanin said she will vote in the runoff but has not decided whether she will make her choice public, adding of the two candidates: "Both are products of the [political] machine.
"It will be four more years of the same," she predicted, referring to the divisive term of current President Ernesto Samper.
Samper has spent most of his administration defending himself against accusations that he knew his 1994 campaign accepted $6 million from Colombian drug lords, who supply about 70% of the world's cocaine.
Serpa was among Samper's most loyal backers. That stance won the hearts and votes of the faithful in the ruling Liberal Party but left him tainted by the unpopular president in the eyes of other voters.
Lacking an outright endorsement from Sanin, each of the two candidates left in the running tried to cast her election night comments in the light most favorable to himself.
"I wish that Noemi had joined us," Pastrana said election night, addressing followers who included Conservative Party regulars, well-known independents and even some disenchanted Liberal Party members in a movement called the Great Alliance for Change.
"Her closing comments were for independence and change, and that is what the Great Alliance for Change represents," Pastrana said. "We invite all the independents who believe in change to join us."
Serpa was more subtle. "I want to recognize that there was a great triumph here: that of Noemi Sanin and her message," he said. "Maria Emma [Mejia, his running mate] and I share her message of reconciliation and nationalism."
When asked whether the votes for Sanin were against him, he replied in a televised interview Monday: "They were different options. . . . They were not against me."
The concern of many analysts is that the disappointed voters who cast ballots for Sanin will stay home next month. It's a worry clearly shared by the candidates.
"Nobody can stay in the stands," Pastrana exhorted election night. "Change requires that everyone play in the game."