On the day when Ferdinand Marcos suddenly imposed martial, Alvarez had been at the University of the Philippines Diliman attending a public forum with Senator Benigno “Ninoy” Aquino Jr.

[2] He went into hiding in various places for a while, but the oppositionists soon suggested that he go to the US to help gather support for their resistance against Marcos, working with Senator Raul Manglapus who had likewise escaped capture because he was overseas on a speaking engagement when martial law was declared.

James Reuter, Alvarez and Guidote were married in a secret "Matrimonia concencia" ceremony in Cavite, with the records sealed in the church's vaults.

Then with assistance from UNESCO Philippines chair Dr. Alejandro Roces, he secretly got onboard a greek ship which took him to Hong Kong, and from there, he went on to the US.

[3] Marsman was accosted by armed men later identified as intelligence agents in June 1974, and his mutilated body was discovered the day after.

Marcelo Alvarez, who had begged Sonny to be more discreet in his opposition to Marcos, died of a heart attack after he learned of Marsman's death.

He won a senatorial seat, representing Isabela province's 4th district, in the post-revolution government of President Corazon Aquino.

In early 1994, Alvarez initiated the "Healthy Air Pact" among three oil companies (Pilipinas Shell, Caltex and Petron Corporation) for them to introduce unleaded gasoline to the Philippine market.