In my career it was both. The real question, depending on circumstances and roles, is what the ratio of leadership to management is. The larger the organization, the more distinct the separation between leaders and managers. Consequently, the greater likelihood of impersonal relationships, conflict, miscommunication, and poor retention. I've seen, heard about, and experienced it. I'd say that in the majority of organizations, leadership & management activities overlap to varying degrees. Significant delineation of these roles may well be the only option for large purely metric driven organizations. Real innovation comes when an organization can replicate the ability of people to implement the varying levels of leadership when they are managing, as well as teaching leaders not to forget the importance of passing down the management skills they may have learned.
In my opinion, interpersonal relationships are rarely cut & dry, this or that, yes or no. I'm no Jack Welch, and GE was a great success story, but I may disagree with him on a couple little things. :)
