Ben: don't you have to get a contract first
: before you actually are "union shop "
: GOOD LUCK
Flint: Short answer is usually yes. The long answer is a bit more complex. First, it depends on what stardard you are using for what is a union and what isn't. Typically speaking most people are under the idea that a union means collective barganing between the employer and the union represenative. That bargaining results in a contract.
Alot of the following information is US specific... but there are general similarties throughout the world where unions are legal.
However, if the employer agrees that a union exists in the shop... it exists (with or without a contract). Likewise, if there is an NLRB (National Labor Relations Board) election and a majority of workers (of a bargaining unit, typically all the workers at one location excluding management) vote for union representation... its a union shop (with or without a contract).
Now there is a question of whether the employer acknowledges the union or not. If they don't, unions often engage in a recognition strike (we aren't going back to work unless you recognizes we are a union). They may legally do this if the employer has violated labor laws or procedures of the NLRB. Legal or not, it is often effective.
The IWW regards a location a union shop by one measurement (which is made up of several factors). Do the workers have control?
Some relevant factors: Can they take action to improve their working conditions? Do union conditions (which usually means the best standards) prevail at the location? Are a majority of workers or more part of the union?
If the Union regards a location as a union shop, then they are authorized to use the union bug on their products. You might notice it on some of the things you buy. Its usually about a quarter inch in size and you can usually just make out which union produced the item. Its an incentive to appeal to consumers to support businesses that have unions.
At one time, the IWW refused to have contracts with employers. The idea was that only worker solidarity and militancy could protect anything that was won by collective action. The bosses, when the first opportunity presented itself would roll everything back (cut wages and benefits, let safety lapse, extend working hours, bring in scabs, bust the union, etc...) However, World War I and II changed working conditions and many companies were willing to agree to contracts in exchange for peace with labor. The US Government helped enforce contracts to keep the war machine going and the economy stable.
I should note that membership in a union can be seperate from the work location, for instance most Wobblies (thats what members of the IWW call themselves) carry their union membership from one job to the next and any unemployment inbetween. We try and get as many fellow workers to join the union as possible before we even start with the authorization cards, an NLRB election or a contract.