Do you agree that ""the employer usually has the upper hand"" when it comes to establishing the employment relationship? When might the employee have maximum power over the employer?

Yes. We have to agree that the employer has the upper hand.

This is mainly because it is the employer that hires the employees initially and decides how. much of a pay will be given.

However their can be times where the employee has the upper hand. If an employee is highly skilled and experienced and worked in the organization for a long time, they might have an upper hand. Also, when there are strict labor rules, this could give upper hand to the employees as well.