The rights of employees to have present a union
representative during investigatory interviews were
announced by the U.S. Supreme Court in a 1975 case
(NLRB vs. Weingarten, Inc. 420 U.S. 251, 88 LRRM 2689).
These rights have become known as the Weingarten rights. 

Employees have Weingarten rights only during investigatory
interviews. An investigatory interview occurs when a
supervisor questions an employee to obtain information
which could be used as a basis for discipline or asks an
employee to defend his or her conduct. 

If an employee has a reasonable belief that discipline or
other adverse consequences may result from what he or she
says, the employee has the right to request union
representation. Management is not required to inform the
employee of his/her Weingarten rights; it is the employees
responsibility to know and request. 

When the employee makes the request for a union
representative to be present management has three options: 
(I) it can stop questioning until the representative arrives. 
(2) it can call off the interview or, 
(3) it can tell the employee that it will call off the interview
unless the employee voluntarily gives up his/her rights to a
union representative (an option the employee should always
refuse.) 

Employers will often assert that the only role of a union
representative in an investigatory interview is to observe the
discussion. The Supreme Court, however, clearly
acknowledges a representative's right to assist and counsel
workers during the interview. 

The Supreme Court has also ruled that during an
investigatory interview management must inform the union
representative of the subject of the interrogation. The
representative must also be allowed to speak privately with
the employee before the interview. During the questioning,
the representative can interrupt to clarify a question or to
object to confusing or intimidating tactics. 

While the interview is in progress the representative can not
tell the employee what to say but he may advise them on
how to answer a question. At the end of the interview the
union representative can add information to support the
employee's case. 

On July 10, 2000, in one of the most significant labor
decisions of the Clinton era, the National Labor Relations
Board extended to nonunion employees the right, already
held by union employees, to bring along a co-worker to a
disciplinary meeting with an employer.
While a challenge is likely, the appeals process could take
months or years. Still, it is unclear whether the decision will
result in big changes in the American workplace, where
roughly 85% of workers aren't represented by a union.
The five-member board overruled a decision in Epilepsy
Foundation of Northeast Ohio and Arnis Borgs and Ashraful
Hasan (331 NLRB No. 92). The administrative law judge in
that case said a 1975 Supreme Court decision. NLRB v.
Weingarten, 420 US 251. granted union employees the right
to bring a co-worker to disciplinary meetings with
employers. But. citing NLRB precedent. he also ruled that
nonunion employees don't have so-called Weingarten rights.
NLRB members John C. Truesdale, Sarah M. Fox and
Wilma B. Liebrnan said the precedent "misconstrued the
language" of Weingarten. While the Weingarten case
involved a union representative, the majority decided that
the court's ruling was based on a section of employment law
that says employees have the right to "mutual aid or
protection."
"This rationale is equally applicable ... where employees
are not represented by a union," the decision states.