Well, if history began on Thursday and everything that had happened before then were a tabula rasa, it would be easy to see the justification for Proclamation 1017. This article from Time Asia shows that there was a coup plot. If the coup plot were the only issue, then the government insistence that Proclamation 1017 saved the country from violence might have been justified.
Of course, because every legitimately elected government ought to protect itself and its mandate from people who might want to bring it down.
And there is where the issue lies. You see, history did not begin on Thursday. The central issue here is not just the coup plot; it is the legitimacy of Arroyo's presidency. Every legitimately elected government ought to protect itself, but is the Arroyo presidency legitimately elected?
The problem, then, is what is perceived by many sectors as this government's attempts last year to suppress legal and constitutional means to investigate the veracity of allegations of widespread cheating by her government during the presidential elections. As long as these issues remain unresolved, any attempts, however lawful, of this government to protect itself will be perceived by many as further attempts to evade the Truth. As long as there is no investigation into allegations of cheating, support for Arroyo will continue to wane and her government will find itself increasingly impotent.
I personally will not throw my support just yet behind any extra-legal means of changing government. Beyond the changing personalities of Philippine government, we need to strengthen our legal institutions, because those are what last beyond the changing names and faces. However, by Jove, I do hope that the President chooses the legal, most sensible, easiest way to get our country out of this stalemate: RESIGN. And let her constitutionally elected successor take the reigns.