JUAN MANUEL SANTOS has demonstrated that pro-American, pro-free-market politicians still have life in Latin America. Mr. Santos, who romped to victory in Colombia’s presidential runoff on Sunday, has no interest in courting Iran, unlike Brazil’s Luiz Ignácio Lula da Silva. He has rejected the authoritarian socialism of Venezuela’s Hugo Chávez. A former journalist with degrees from the University of Kansas and Harvard, he values free media and independent courts. His biggest priority may be ratifying and implementing a free-trade agreement between Colombia and the United States.

So the question raised by Mr. Santos’s election is whether the Obama administration and Democratic congressional leaders will greet this strong and needed U.S. ally with open arms — or with the arms-length disdain and protectionist stonewalling to which they subjected his predecessor, Álvaro Uribe.

Mr. Uribe will leave office in August as one of the most successful presidents in modern Latin American history, though you would never know it from listening to his critics in Washington. He beefed up Colombia’s army and economy, and smashed the terrorist FARC movement; murders have fallen by 45 percent and kidnappings by 90 percent during his eight years in office. Though most Colombians wanted him to remain in power, he bowed to a Supreme Court ruling against a referendum on a third term — which means that unlike Mr. Chávez, he will leave behind a strong democratic system.

Colombia has nevertheless been treated more as an enemy than friend by congressional Democrats, who have steadily reduced U.S. military aid and worked assiduously to block the free-trade agreement Mr. Uribe negotiated with the Bush administration. The Obama administration, which has courted Mr. Lula and sought to improve relations with Venezuela and Cuba, has been cool to Colombia, recommending another 11 percent reduction in aid for next year and keeping the trade agreement on ice.

Mr. Santos’s election offers an opportunity to revitalize the relationship. As defense minister, he demonstrated a commitment to addressing the human rights concerns that troubled some in Congress. He has pledged to seek better relations with both Venezuela and Ecuador, despite the material support those countries have provided to the FARC.

Ratification of the free-trade agreement would serve the administration’s stated goal of boosting U.S. exports while bolstering a nation that could be an anchor for democracy and political moderation in the region. It would also allow the administration and Congress to demonstrate that friends of the United States will be supported and not scorned in Washington.

###