According to ricelander.wordpress.com
"Marcos declared Martial Law because of Ninoy Aquino.
Ninoy Aquino was the new political superstar of the time. In all likelihood, he was going to be the next President. But Ninoy was perceived rightly or wrongly as a communist, or at least sympathetic to the communist movement that was leading the social unrest threatening to engulf the country.
The constitutional option for Marcos had run out. The explosive bribing scandal that exposed his attempts to influence the delegates to the Constitutional Convention of 1972 to allow him to run again killed that alternative.
It was at the height of the communist movement’s popularity. For a society beset by severe social inequity and grinding poverty like the Philippines, communism certainly provided a stark alternative, with its own powerful mass appeal, to challenge the unjust status quo. In fact, Southeast Asia then, in particular Vietnam, Cambodia, Laos, ( as in Korea), was fast being run over by the Communists, due to the huge support of the people." - source ricelander.wordpress.com
It is hard to believe that claim unless you go back to the past and know the late President himself and Ninoy. For those who were around during the Marcos days, especially in the 1960s, the country was super booming it was an indeed a progressive country at that time and it was the reason that the late President was claimed as the best President in the world. If the country was that booming why there were protest in the Philippine capital?
According to http://www.gov.ph/edsa/the-ph-protest/ read below