Labor Unions are formed by employees to ensure that management does not unfairly or unethically distribute work and profits; they are chiefly concerned with collective bargaining for all employees so that fair practices and fair treatment are ensured all over the company.
Normally, unions pass a ballot of initiatives for members to sign, and the ballot is then adopted as policy and presented to management. Assuming the ballot is amicable and there are no outright abuses occurring, the union bargains with management to secure the initiatives for its members. If the two parties cannot reach an agreement, the union has the power to takes its members on strike, potentially crippling the business until they agree. Lawyers on both sides examine the ballot for loopholes. Many unions revise their initiatives every year, and the large trade and industrial unions are able to influence businesses around the nation, not just in their area. The basic idea of a union is to keep management from abusing certain members of the workforce by advocating an "all-or-nothing" position; one common motto is "An injury to one is an injury to all."
In the United States, labor unions saw their peak influence in the 1950s, with participation and efficacy lowering in recent years. However, many large unions like the Service Employees International Union (SEIU) continue to have and enforce great influence both in the working world and in politics. The major weapon of labor unions is the threat of strike; almost all businesses will capitulate in the face of shutdown and losing revenues. However, many unions never worry about striking, instead meeting with management and leadership several times a year to bargain for better conditions, pay, and influence in the company for their members. Normally, union influence only covers employees who are members of the union, but there is a push to implement a "Card Check" rule for unions to act immediately if 50% or more of employees sign off, instead of the current secret ballot.