Many factors contributed to the downfall of Pres. Marcos, amongst them: the declaration of Martial Law 
which he defended vigorously even to the extent of naming it to The Birth of A New Society.

1973 and 1977 presidential elections was suspended when the country was in the state of Martial Law.

On paper Martial Law was lifted in 1981.

Martial Law 5th Anniversary Issue Presentation Folder
September 21, 1977

Metal cliché specimen strikes employed by the Post Office
during the 1977 5th Anniversary of the Declaration of Martial Law

Renaming Martial Law into the Birth of A New Society made the people more receptive to Pres. Marcos authoritarian regime. Peace and order was restored at the expense of real democracy. He also established a new party called the Kilusang Bagong Lipunan (The New Movement Party) or simply KBL.
As Pres. Marcos stay in power lengthened those opposed to his authoritarian rule started
to voice out criticisms, foremost was the amassing of ill gotten wealth through loans from the 
World Bank and International Monetary Fund that only benefited his closest allies.

International Monetary Fund and World Bank Board of Governors Meeting
issue of October 4, 1976 on 1981 commercial cover postmarked
CANLUBANG, LAGUNA to QUEZON CITY