Colombian President Alvaro Uribe's visit to Washington this week comes at a time of increased optimism for his country's decades-long campaign to defeat leftist guerrillas and combat the illegal drug trade. Signs of progress are critical as Colombia presses for continued U.S. aid, and as both nations contemplate a possible tree trade accord.

It was just two years ago that many Colombia observers openly questioned whether the country was teetering on the edge of becoming a failed state. The signs were ominous: leftist rebels were seizing larger and larger swaths of Colombian territory, drug production was again on the rise, and killings and kidnappings were as prevalent as ever.

Today, 18 months into his administration, Colombian President Alvaro Uribe can point to some concrete accomplishments. Mr. Uribe spoke with reporters after meeting with President Bush at the White House Tuesday. "Last year, kidnappings fell by 27 percent and continue to decline this year. Homicides fell by 22 percent and are also declining this year," he said.

President Uribe has directed an aggressive military campaign against Colombia's two leftist insurgencies. Whereas his predecessors ceded vast stretches of territory to the rebels, even allowing them to create a quasi-rebel administration in a demilitarized zone south of Bogota, President Uribe has reclaimed guerrilla-held lands and sought to crush the insurgents wherever possible.

"The progress [in Colombia] has been impressive by any measure," said Michael Shifter, who specializes in Colombian affairs at the Washington-based Inter-American Dialogue. "The state, the government is becoming stronger. The police have a greater presence in many municipalities throughout the country. The armed forces are becoming more capable of protecting Colombians. The decline in kidnappings and homicides and massacres are very impressive."

But for President Uribe, the battle to forge a peaceful nation is far from over. The Colombian leader compares violence and lawlessness to a dangerous snake that has yet to be killed.

"The snake is still alive. But the snake cannot be allowed to survive," he said. "The plan must continue. If we do not press on until we kill the snake, it will bite us even more viciously in the future."

The Colombian leader says continued U.S. assistance is critical if ongoing efforts in his country are to succeed. In 2000, the United States launched a multi-billion dollar project designed to strengthen Colombia's security forces and its democratic institutions. Known as "Plan Colombia," the project devoted considerable resources to boosting the country's counter-narcotics operations. But U.S. military cooperation is also credited with increasing Colombia's effectiveness in fighting insurgents.

Plan Colombia is set to expire next year. Michael Shifter says there is ample cause for renewing and even expanding U.S. assistance. "Plan Colombia was a contributing factor to the success of the situation turning around [improving]," he said. "The task and challenge is to make sure that success is an enduring one. And I think it is very hard for the Colombians to do that without continued support. So, I would think that a second phase [of Plan Colombia] - perhaps oriented to institutional reform, social reform, political reform, judicial reform - is also critical. And I think the United States does have an opportunity and a responsibility in looking ahead with Colombia."

Colombia is also eager for a bilateral free trade accord with the United States, which could take a year or longer to negotiate.

But not everyone thinks President Uribe should be rewarded with U.S. aid and a trade agreement. Amnesty International USA's Advocacy Director for the Americas, Eric Olson, says, under President Uribe, Colombia's security forces remain one of the hemisphere's worst institutions when it comes to human rights.

"Anytime there is an armed conflict, it leads to violence and suffering," he said. "But it does not necessarily have to lead to human rights violations. It is not an acceptable trade-off to say, 'Well, we have to defend ourselves - therefore we can violate human rights.' That is unacceptable in this country [the U.S.] and it is unacceptable in Colombia."

Mr. Olson notes that right-wing para-military groups and leftist guerrillas are also responsible for horrific human rights abuses in Colombia.

"There is no faction of this conflict that can be considered above reproach," he said.

Reports from Bogota say Vice President Francisco Santos gave a testy response when asked about a United Nations report critical of Colombia's human rights record. Mr. Santos was quoted as saying that the United Nations does not understand that Colombia's government faces enormous threats by armed groups who want to destroy democracy.