He said that the Supreme Court must guarantee that the ghost of Marcos' martial law must not be repeated.
"The ghost of Marcos' martial law lives within the words of our Constitution and rightly so. That ghost must be exorcised with passion by this Court whenever its resemblance reappears," the justice said.
Leonen was an appointee of former President Benigno Aquino Jr. He pointed out to consider the cry of anti-Marcos protesters who are until now, passing on their grief and anger to their next generations.
"Never again should this court allow itself to step aside when the powerful invoke vague powers that feed on fear but could potentially undermine our most cherished rights... We should have the courage to never again clothe / authoritarianism in any disguise with the mantle of constitutionality," Leonen said.
He wrote on his twitter that the siege in Marawi City is not caused by rebellion, thus, his conscience couldn't see the need to declare martial law in the conflict-stricken city.
"With due respect to my colleagues, I cannot join them in their acceptance of the President's categorization of the events in Marawi as equivalent to the rebellion mentioned in article VII section 18. In conscience I do not see the situation as providing for the kind of necessity for the imposition of Martial Law in Marawi as well as throughout the entire Philippines.
"Rather, I read the situation as amounting to acts of terrorism which should be addressed in a decisive but more precise manner. The military can quell the violence. It can disrupt many of the planned atrocities that may yet to come. It can do so as it had on many occasions in the past with the current legal arsenal that it has."
Leonen was the sole Justice who granted that the petition of the groups to dismiss martial law proclamation in Mindanao for allegedly having no factual basis. However, the Supreme Court ended with votes of 11-3-1 in favor of President Rodrigo Duterte's martial law proclamation.
Leonen was previously the chief peace negotiator under the Aquino administration.
He said that the militants in Marawi City shouldn't be acknowledged as rebels but terrorists. "I honor the sacrifices of many by calling our enemy with their proper names: terrorists capable of committing atrocious acts. They are not rebels desirous of a viable political alternative that can be accepted by any of our societies. With their plans disrupted and with their bankrupt fanaticism for a nihilist apocalypse, they are reduced to a fighting force violently trying to escape. They are not a rebel group that can hope to achieve and hold any ground," Leonen said in his dissent.
The Solicitor General admitted during the oral arguments that martial was meant to make terrorists listen.
"We should temper our fears with reason. Otherwise, we succumb to the effects of the weapons of terror. We should dissent – even resist – when offered the farce that Martial Law is necessary because it is only an exclamation point," Leonen said.
"In my view, respondents have failed to show what additional legal powers will be added by Martial Law except perhaps to potentially put on the shoulders of the armed forces of the Philippines the responsibilities and burdens of the entire civilian government over the entire Mindanao region. I know that the Armed Forces of the Philippines to be more professional than this narrative."
Supreme Court's majority ruling paved the way for President Duterte to put the entire Philippines under martial law if necessary. However, the sole dissenting Justice said that the Proclamation 216 is only hiding its real intentions and that is to expand to the entire nation.
"Arresting illegal drug syndicates and peace spoilers under martial law also unduly expands Proclamation No. 216. The factual bases for the declaration of martial law as presented by the respondents do not cover these illegal acts as rationale for its proclamation. They do not also fall within the concept of rebellion," Leonen said.
"The scope of martial law as contained in Proclamation No. 216 issued last May 23, 2017 expands with every new issuance from its administrators. Proclamation No. 1081 of 1972, which ironically was more specific, evolved similarly," Leonen added.
Source: CNN, Rappler