For most workers, organizing a union is the only way to legally require an employer to negotiate in good faith over wages, hours and terms and conditions of employment. Without a union, employers are free to change the rules at any time, and do not have to be accountable to their workers for these changes. With a union, the parties have a duty to share relevant information, and bargain in good faith. Many employers spend a significant amount of money and effort to oppose union organizing drives. Some employers, however, do more than spend money trying to persuade their workers to vote against unions. They might use threats, intimidation, or retaliation to make workers afraid of losing their jobs if they support the union. These measures are illegal.