One of your most important rights is the right to organize.  In fact, the government protects your rights to join a union.  It is against Federal Law for your boss to fire you for:

Talking to a union organizer

Attending a union meeting

Joining a union

Signing a union card

Wearing a union button

Here are your rights as stated in the National Labor Relations Act (as amended in 1947 as the Labor-Management Relations Act) which was adopted by Congress as the Law of the Land.

Section 7: Employees shall have the right to self-Organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection...

Section 8 (A): It shall be an unfair labor practice for an employer-8(A) 1. To interfere with, restrain, or coerce employees in the exercise of the rights guaranteed in section 7;

8(A) 3. By discrimination in regard to hire or tenure of employment or any term or condition of employment to encourage or discourage membership in any labor organization.

In Addition:

The Federal Courts have held that it is illegal for your employer to interfere with your rights by:

Making threats of loss of jobs or benefits

Making promises of promotions, pay raises, or other benefits.

Making threats of physical force or violence.

You also have the right to have a shop steward accompany you with any discussions with your employer.

This is your Weingarten Rights.  It states: "If this discussion could in any way lead to my being disciplined or terminated, or affect my personal working condition, I respectfully request that my union representative, officer, or steward be present at the meeting.  Without representation, I choose not to answer any questions."

You should invoke this right whenever you fear that what you say may affect your position.