Justice should be tempered by mercy. That was the thinking of the government of Scotland when it decided to release Abdel Basset al-Megrahi, who is suffering from terminal cancer, from prison, eight years into a 27-year minimum sentence for blowing up an airliner over Lockerbie, Scotland, and killing 270 people.

But that show of humanity has unleashed a firestorm of controversy. Critics argue that compassion from the government should be matched by a similar demonstration by al-Megrahi himself, a step he has never taken. More disturbing still are reports that the Scottish decision was influenced by the British government's desire to improve ties with Libya. London has vehemently denied the accusation, but questions linger, clouding an already emotional and difficult decision.

Pan Am flight 103 exploded in midair over Lockerbie, Scotland, in December 1988, claiming 270 lives. The atrocity triggered the largest law enforcement investigation in British history, one that concluded in murder indictments against al-Megrahi, then a Libyan intelligence officer, and Mr. Lamin Khalifah Fhiman, the Libyan Arab Airlines station manager in Malta. After protracted negotiations with the Libyan government, the two men were handed over and a special court was convened in 1999. In January 2001, the court found al-Megrahi guilty of murder while acquitting Mr. Fhimah. Eight years into his sentence, al-Megrahi was released on compassionate grounds: He suffers from prostate cancer and is said to have but three months to live.

The decision to free al-Megrahi outraged the families of the victims, law enforcement officials, and the United States government. The director of the U.S. Federal Bureau of Investigation, Mr. Robert Mueller, who led the investigation of al-Megrahi, sent a letter to Mr. Kenny MacAskill, the Scottish justice secretary who approved the release, saying, "Your action makes a mockery of the rule of law," insisting that the move was "as inexplicable as it is detrimental to the cause of justice."

U.S. and British officials condemned the hero's welcome al-Megrahi received upon returning home, calling it "outrageous" and "disgusting." The anger was magnified by Tripoli's disregard for warnings from Washington and London that a public spectacle would be inappropriate. Libyan officials brushed off the complaints. Leader Moammar Gadhafi even used the occasion to make mischief, calling British Prime Minister Gordon Brown "my friend" and thanking him for pushing the Scottish government to free al-Megrahi.

Mr. Brown, along with other ministers, insisted that neither he nor anyone else in his government applied any pressure on the Scottish government. "On our part, there was no conspiracy, no coverup, no double-dealing, no deal on oil, no attempt to instruct Scottish ministers, no private assurances by me to Col. Gadhafi."

Indeed, the decision to free al-Megrahi was for Scottish officials to make and, after the devolution of power to Britain's regions during the past decade, the London government had no input into it. Mr. Alex Salmond, leader of the Scottish government, said his government was driven by compassion for a dying man. Mr. MacAskill added that the humanity behind his ruling was "a defining characteristic of Scotland and the Scottish people."

While Britain has no official say in the decision, questions have been raised by its handling of the matter. Mr. MacAskill said requests for advice from London were met with silence, suggesting that it did not feel strongly about the issue. More troubling is the release of letters between Libya and Britain in which Tripoli warns that the death of one of its nationals in a Scottish prison would have "catastrophic effects for the relationship" between the two countries. This was part of a broader negotiation over the terms of a prisoner transfer agreement (PTA), in which a key question was whether al-Megrahi would be included.

At the same time, British companies were discussing investment in Libyan oil fields, in particular, a $900 million deal involving BP, as well as others. Again, the denials have been loud and heartfelt. British Foreign Minister David Miliband said it was "a slur both on myself and the government" to suggest that oil was a factor in the decision and the Foreign Office flatly denied there was "any deal in relation to Megrahi and any commercial interests in Libya."

In fact, the British position changed: After initially supporting leaving al-Megrahi out of the PTA, the British justice minister told Mr. MacAskill that it did not make sense "to risk damaging our wide ranging and beneficial relationship with Libya by inserting a specific exclusion into the PTA."

There is another troubling element of this tale: the lack of remorse by al-Megrahi himself. Some would say that compassion to him should be matched by compassion by him. He should show some feeling for the victims and to their families. Instead, he continues to insist on his innocence, a view that seems to match that of his government.

When Tripoli accepted responsibility for the Pan Am attack, its letter to the United Nations merely "accepted responsibility for the actions of its officials." If he was innocent — and the Scottish Criminal Cases Review Commission ruled in June 2008 that al-Megrahi "may have suffered a miscarriage of justice" — then he too is another victim of the games played by nations. Justice tempered by realpolitik is not justice at all.