On the one hand, it cannot be seen leaning on the Libyan authorities to interfere with the judicial system, which the EU itself says must be independent in its partner countries.
On the other hand, the EU has agreed with Bulgaria that the trial was suspect and crucial evidence was mishandled. And, as Bulgaria is expected to join the EU in 2007, its appeals for solidarity cannot be ignored.
Returning from her trip to Tripoli, Ferrero-Waldner dropped what could be the first hint that there might be light at the end of the tunnel for the six medics. Speaking to journalists in Brussels, the commissioner said she had had "moving" meetings with the infected children's families -- whose consent is believed to be essential if the medics are to be freed.
"I must say, having seen a slightly moving climate with the families who were also moved by our visit there, I do hope there is somewhat a slight flame of hope," Ferrero-Waldner said.
AFP reports from Tripoli that Libyan Prime Minister Shukri Ghanem said yesterday he had told Ferrero-Waldner Europe needs to "take an interest also in the situation of the families of the victims."
Libya has also said it wants compensation for 426 children infected with the AIDS virus at the Benghazi hospital where the medics worked. Ferrero-Waldner indicated yesterday that the EU prefers to offer assistance to upgrade the country's health sector and secure "the best" treatment for the affected children.
"We the European Union have come with our action plan, and this action shows three important points," Ferrero-Waldner said. "One is quality care for the children, the second is, we try to show also what we have done in Europe on the different points [including] best-ever medical care, a system of medical care, the right way of treatment."
Other elements in the EU plan outlined by the commissioner include steps to reintegrate the infected children into their families.
The six medics -- who say their confessions were extracted under torture -- now await the decision of the Libyan Supreme Court, which is due to consider their appeal on 31 May.
Bulgarian President Georgi Parvanov will visit Tripoli on 27 May in one last attempt to sway Libya's leader, Colonel Muammar Gaddafi.
Ferrero-Waldner, who met the medics yesterday, said they appeared in good shape but added that the ordeal was taking a heavy mental toll.
"I can tell you that physically the nurses and also [Palestinian] Dr. Asharaf seem to be in good condition, but I think they are psychologically tired," Gaddafi said.
Ferrero-Waldner also indicated that the case could harm Libya's chances of joining the EU's so-called Barcelona Process, which offers trade and development benefits to countries on the southern and eastern coast of the Mediterranean Sea.