"Examinemos la realidad, más allá de la propaganda y la retórica."
This is the main purpose in Enrique Encinosa's article, La Verdad sobre Luis Posada, telling the reader to "examine the truth, beyond the propaganda and rhetoric." I agree, let's proceed.
Encinosa provides 5 points to proclaim the innocence of Luis Posada Carriles to the bombing of the Cubana Airline flight in 1976.
1) Luis Posada Carriles "voluntarily submitted" to a lie detector test whose results showed he was not involved in the bombing of 1976;
2) Posada Carriles was "acquitted on two occasions" in Venezuelan courts, namely in 1980 by Judge José Moros González;
3) Testimony by Osmeiro Carneiro, made in El Nuevo Herald on July 15, 1991, declaring that Orlando Bosch and Luis Posada Carriles were "innocent" and "scapegoats";
4) Testimony by Ricardo "El Mono" Morales Navarrete confessing to a conspiracy with Cuban intelligence agents to blow up the Cuban airline flight and blame Bosch and Posada;
5) An FBI report "declaring" that Luis Posada Carriles was not involved in the 1976 bombing.
THE LIE DETECTOR
Its important to note that Luis Posada Carriles "voluntarily submitted" to a lie detector test right before he entered the US in 2005 and was accused of illegal entry, and his past history placed under suspicion by the FBI. More likely that the polygraph was the idea of his attorneys and not solely of Posada, already knowing that they would face legal troubles. Not voluntary at all it seems. Nevertheless, polygraph tests have been shown to be very unreliable and its results are not allowed in federal courts as evidence. The website AntiPolygraph.org provides many examples to support the unreliability of such tests. This test alone does not prove the "innocence" of Luis Posada Carriles, but instead is a legal strategy by Posada's lawyers who can use the polygraph examiners testimony to claim innocence for their client, which is allowed in court.
According to the judicial record, Luis Posada Carriles has never been acquitted twice. Encinosa is correct in stating that he was acquitted in 1980, but this only counts as ONE. According to what has been officially submitted to the Inter-American Commission on Human Rights (IACHR) of the OAS in 1984, the initial civilian court that brought charges on Posada Carriles never made an acquittal, but instead on "August  1977, [Judge] Dr. Delia Estaba decided that this case was not within her competence, and referred it together with the records, to the Military Courts, specifically to the First Military Court of First Instance."
Only in 1980 was Posada acquitted by José Moros González. Still, this decision was invalidated in 1983. According to the submission to the IACHR:
"On March 24, 1983, the Court Martial declared itself incompetent to handle the case, based on a recent ruling of the Supreme Court of Justice, in deciding in the case of a woman journalist, that persons must be judged by their natural judges; it decided to send the case, consisting of 23 pieces plus the exhibits, to the Superior Judge, XIV Criminal Court, José Erasmo Pérez España, and to submit the conflict of competence to the Criminal Chamber of the Supreme Court of Justice."
According to Jose Pertierra, a Cuban-American lawyer representing Venezuela in its extradition of Luis Posada Carriles, the decision in 1983 means "that the lower Court’s decision is annulled, and that the entire record of the case is void, much akin to the legal effect that an annulment has on an attempt at a marital union."
Rosa Miriam Elizalde, a Cuban journalist, and José Pertierra write about the "Double Acquittal Myth" of Luis Posada Carriles, and explain that in this case "[a] lie, if repeated often enough, turns into truth."