Santos spelled out his strategy as he requested increased defense funding from Congress to ensure the Colombia military's readiness for all eventualities if the talks, due to begin Oct. 8 in Norway, fail to produce a deal with the guerrilla group, known by its Spanish-language initials of FARC.
Independent security analysts say the rank and file of FARC is depleting but there are still about 8,000 activists under arms, involved with fighting government forces and drug trafficking that finances weapons purchases and cash flow.
Independent confirmation of FARC's current strength is scarce but disenchantment with FARC and the guerrilla group's less than idealistic dependence on drug trade isn't just government propaganda, analysts said.
FARC activities continue to claim innocent lives, including casualties among children said to have been recruited by the group for paramilitary and smuggling duties. Damage to Colombia's infrastructure from FARC activities costs at least $50 million a year.
Santos said he hoped to report to the United Nations next year with news of a peace breakthrough. The president has been visiting the United Nations to champion Colombia's position and build up his profile as a peacemaker, military strategist and tough negotiator all rolled into one.
"I am optimistic, cautiously optimistic," Santos said in an address to the Americas Society in New York. He said "conditions are there" for a peace settlement but his administration is not abandoning the alternative of continuing military operations until victory over FARC.
Analysts said Santos needs to contend not only with FARC but with smaller armed groups, too. As in Northern Ireland and other violence-ravaged situations, a peace settlement will likely produce dissenting voices and draw disgruntled elements into splinter groups opposed to any peace package with the government.
Santos said he wants the peace process to be over within months not years.
"If we are successful, imagine what Colombia would look like," he said.
The government's annual defense spending is likely to rise to $14.5 billion -- about 15 percent of an overall $130 billion national budget.
Santos outlined plans to destroy most of cocaine producing crops, capture aircraft and submersibles used by drug overlords and FARC allies.
However, before that stage is reached, government negotiators and FARC will need to agree on the terms of a settlement. FARC wants a general amnesty and protection against extradition of suspects to the United States. Santos has ruled out both.
FARC leader Timoleon Jimenez in a broadcast from Havana said the group is committed to a "civilized dialogue" that would end the decades-old conflict.
Colombian opinion polls have backed Santos on the talks but opposed any political accommodation. About 77 percent of those polled said they favor negotiations with FARC but 72 percent oppose the eventual participation of FARC in politics, while 78 percent don't approve an amnesty without jail terms for guerrilla commanders.
Santos is also facing internal political opposition, not least from former president Alvaro Uribe, whom he served as defense minister.