[JURIST] The National Union of People's Lawyers (NUPL) [advocacy website] and other groups on Monday petitioned the Philippines Supreme Court [official website] to reject a proclamation [text, PDF] by President Gloria Macapagal-Arroyo [official website; BBC profile] imposing martial law [JURIST report] and suspending habeas corpus in the province of Maguindanao. The groups claim that Arroyo exceeded her constitutional authority [Philippine Daily Inquirer report] to impose martial law by making the proclamation in the absence of either a rebellion or invasion, the two circumstances in which martial law is allowed under Article VII Section 18 [text] of the Philippine Constitution. As mandated by the constitution, the Congress of the Philippines [official website] will review [press release] the proclamation on Tuesday and decided whether to support the move by a majority vote.

The proclamation was announced [press release] on Saturday, and is a result of instability in the province following a politically motivated attack that left 57 dead last month. Government authorities on Friday arrested several suspects [BBC report] in connection with the attack, including Maguindanao Governor Andal Ampatuan Sr., and subsequently discovered an "arsenal of weapons" buried nearby. Military officials believed that rebels loyal to the Ampatuan family intended to launch a rebellion. The family is suspected of ordering the November 23 attack [AFP report] against political rival Esmael Mangudadatu, who was traveling with family, aides, and journalists to file as a candidate in an upcoming gubernatorial election.