The members are the eyes and ears of the union. When organizing opportunities are discovered they can inform the Local. So, it is useful to have some information on what the law is on the subject.
In the past if an employer used a temporary service like Manpower, you could only seek to organize the regular employees of the employer. The temporary employees were blocked from the campaign unless their employer consented to them being included. Fat chance of that happening!
Now after the NLRB' s recent Miller & Anderson decision all the employees working at the user's business can be included in the same unit, at the option of the union. The employer must bargain for all of them. With reference to the supplied employees he must bargain over the terms and conditions of employment that he controls. This new rule will increase the power of the union by combining all employees into one unit.