Academic and businessman Rabelani Dagada has officially announced his intention to run as the DA's Joburg mayoral candidate - competing against Black Like Me founder Herman Mashaba. Dagada, a Wits academic and business consultant, said in a letter to DA leaders yesterday he had decided to participate in politics "because the threat to democracy is really staring us in the face".He said he could deliver on both requirements for a mayoral candidate: the ability to win an election, and be a good mayor.In an interview yesterday, Dagada said should he be successful, he would immediately resign from his job and give up writing for the SA Institute for Race Relations, where he is a policy fellow."Each time I write something, or tweet something or put it on Facebook it must be about the DA. I must just have the one identity," he said."Once you actively join politics as an intellectual, your readers and listeners start to doubt your objectivity. I find this kind of doubt to be justifiable. On the other hand, I had always wanted to write, criticise, and praise both the DA and ANC without worrying about being seen as a traitor," he said.The closing date for nominations for candidates is next Monday...