According to him, President Nana Addo Dankwa Akufo-Addo and the security have failed to protect Ghanaians.
Mahama, addressing party supporters said the NDC will match the NPP boot-for-boot in the 2020 elections if the government attempt to intimidate and harass its supporters.
The warning comes on the heels of a shooting incident at the at Bawaleshie JHS polling station in the course of the Ayawaso West Wuogon constituency by-election on Thursday, 31 January 2019.
Asiedu Nketia said he supports Mahama for his actions adding that members of the party would provide their own security if the police fails.
He noted that the emergence of vigilante groups is an appropriate response to the failure of the NPP government to control its vigilante groups.
"Those criticizing Mahama are doing so because they feel like criticizing. In fact, everything he said was right and I support him totally. Akufo Addo and his security people have failed to protect us so the best we can also do is to face them," Asiedu Nketia said on Accra-based Okay FM.