Boundaries.

A Leader defines the Space in which those who join her will apply themselves towards the Purpose.

A Leader clearly marks out the boundaries - not as an exercise of power to restrain or control those following but as a shorthand way of defining the resources - time, money, laws, staff, decision-making authority - available to them. It removes as many variables as possible so that she can leave them to focus on doing good work.

The space is marked out in the job ad, the employment contract, the duty statement, policies, procedures, budgets. Practical, unambiguous boundary lines around a field of endeavour and creativity and good work.

A good Leader will make the space as large as practicable to allow those within it the freedom to explore and experiment and innovate.

She may have managers who patrol the boundaries on her behalf. (Many 'leadership' positions are actually caretakers of a boundary of the Space carved out by a Leader.)

Some people's response to boundaries is to run as fast as they can to the extremes of the space and pound on the walls. A few will even cross over them as a child-like expression of their independence or dissent from the Leader. Others will probe the boundaries for technical gaps and exploit them, only to retreat back inside and feign surprise and indignation when asked to account by the managers for their actions.

The Leader responds by inviting them to leave her space and create their own.

As she will soon do herself. 

The Leader's final act is to Retreat from the Space that she has created for others to fill.  

So that she can define a new one.

And so on. 

Because that's what Leaders do.