Carter took the excuses of the apartheid government at face value: “They’ve claimed to have withdrawn and have not left any South African troops in Angola. So we hope it’s just a transient strike in retaliation, and we hope it’s all over.”
Granting the racist South Africans a blanket diplomatic shield at the UN and allowing them free reign to terrorize their neighboring Southwest African countries at will, while subjecting their own domestic population to the crime against humanity of apartheid, would prolong the suffering of millions of Africans for another 15 years.
Meanwhile, Carter and his administration would continue demanding the immediate exit of the Cuban military from Angola. As many as 30,000 Cuban troops had been stationed in Angola since 1975 to prevent South Africa from toppling the nascent revolutionary MPLA government and installing a puppet regime that, according to historian Piero Gleijeses, "would be the centerpiece of the Constellation of Southern African States that [South Africa] sought to create." The constellation would be "anticommunist, tolerant of apartheid, and eager to persecute [Nelson Mandela's] ANC and [Namibian liberation movement] SWAPO." 
“US foreign service officers had been meeting with Moujahedeen leaders to determine their needs at least as early as April 1979," writes Blum. "And in July, President Carter had signed a ‘finding’ to aid the rebels covertly, which led to the United States providing them with cash, weapons, equipment and supplies, and engaging in propaganda and other psychological operations in Afghanistan on their behalf." 
Blum says that intervention by the US and other countries worried Russia about what kind of government would end up on their borders. The Russians, Blum writes, "consistently cited these ‘aggressive imperialist forces’ to rationalize their own intervention in Afghanistan, which was the first time Soviet ground troops had engaged in military action anywhere in the world outside its post-World War II Eastern European borders.” 
Soviet troops would enter Afghanistan on Christmas Eve, 1979. By the time they left in disgrace ten years later, the country was largely reduced to rubble. The devastation was so severe that the Taliban, who managed to displace the barbaric Moujahedeen, were seen by many as liberators.
It would be another 22 years before the U.S. experienced blowback on its home soil, when one of the "Anti-Soviet warriors" they had courted and helped train from Saudi Arabia would mastermind a plot to turn civilian airliners into missiles that were flown into the World Trade Center and the Pentagon.
In the last few days news has appeared in the national press that worries me greatly: according to the reports your government is studying the possibility of economic and military support and assistance to the present junta government.
Because you are a Christian and because you have shown that you want to defend human rights I venture to set forth for you my pastoral point of view concerning this news and to make a request.
I am very worried by the news that the government of the United States is studying a form of abetting the arming of El Salvador by sending military teams and advisors to ‘train three Salvadoran batallions in logistics, communications, and intelligence.’ If this information is correct, the contribution of your government instead of promoting greater justice and peace in El Salvador will without doubt sharpen the injustice and repression against the organizations of the people which repeatedly have been struggling to gain respect for their most fundamental human rights.
His Carter Center also has done extensive work studying voting systems and certifying the validity of electoral processes. In 2013, Carter debunked Secretary of State John Kerry's description of the Venezuelan election of Nicolas Maduro as questionable by stating that that the voting was "free and fair." This was an strong counterweight to American state propaganda, which sought to empower the losing Venezuelan opposition by refusing to grant legitimacy to the socialist, democratically-elected government.