The 13th Congress of the Philippines (Filipino: Ikalabintatlong Kongreso ng Pilipinas), composed of the Philippine Senate and House of Representatives, met from July 26, 2004, until June 8, 2007, during the fourth, fifth, and sixth years of Gloria Macapagal Arroyo's presidency.

President Gloria Macapagal Arroyo, in her several State of the Nation Addresses has repeatedly called on Congress to pave the way for the amending of the 1987 Constitution[1] to provide for a unicameral–parliamentary–federal form of government.

On December 8, 2006, the administration-dominated House of Representatives, bypassing the Senate, passed in haste House Resolution 1450, which called on Congress to convene into a Constituent Assembly (ConAss) to propose amendments to the Constitution.

[2] The House move however, was faced with stiff opposition from the outmaneuvered members of the opposition and all but 1 member of the Senate,[3] which was later bolstered by support from several sectors of the civil society and the influential Roman Catholic Church,[4] which threatened to hold nationwide protest rallies to denounce the House move.

[5] Succumbing to the mounting opposition and the apparent withdrawal of support of the President,[6] House Speaker Jose De Venecia later on scrapped the entire resolution and called instead for a constitutional convention, challenging the Senate to concur it in 72 hours.