In my experience, and the theory I've been reading for my degree, a couple of things come to mind.
From the employer's point of view:
In a loose (ie lots of people wanting work) labour market:
1. Low skilled employees are expendable
2. The less conditions, the more flexible the workforce (ie part time, no penalty shift loadings)
3. Need to keep costs down to satisfy the profit motive, easiset way to lower costs is to lower the largest (and easiest) cost element in the production process -- cost of labour.
Therefore, unions suck. They tend to drive up costs of labour by requiring such things as "meal breaks", minimum hours off between shifts, loadings/penalties for night work.
In a tight labour market:
1. Low skill employees expendable
2. Need to keep/attract best staff by offering good pay/conditions
3. Slackers tend to keep their job because there's no one else to hire (but first in line to go when business reduces)
Unions STILL suck.
From Employee's POV:
Tight labour market:
1. Protect rights at work by enforcing meal breaks, rest periods. Prevent price under cutting by scabs, foreign imported labour.
2. Provide a consolidated voice for individuals in a weak negotiating position.
3. Provide information and support when things go wrong such as workplace injury or harassment or managerial bullying.
Loose labour market
1. Prevent business from undercutting wages
2. Ensure the employees can have a voice at the table.
This being said, as a former base level employee, I was glad for the union at times, but for the most part, they had a political agenda, and used their collected dues to further the political careers of the people at head office, and a little bit of advocacy for members. Mostly career advancement for the wannabe politicians.
I see the capitalist motive in play in a lot of organisations that will do WHATEVER it takes to remove power from the employees, including the right to assembly (unionism). Think Big Box store WallyWorld who actively stamp out union organising.
So, if an organisation actually cares about its workforce, their health and wellbeing, f##k the union. But where an employer is simply trying to cut costs by f##king the employee over, get them in to kick some heads.
Don't forget, many organistions belong to 'unions' of a kind; industry groups, think tanks, professional associations, business councils.
In terms of leaving jobs, not everyone has the self esteem, self awareness or financial means to just up and leave, nor even take a day off to go to an interview. Secondly, not everyone lives in a city/town where there are multiple employers.
An example of where de-unionising has worked really well: Harley Davidson in Kansas(?). They opened a new plant, kept 5% of the workforce, hired new peope for the remaining jobs. They cut the lead time on custom bikes from 2 yrs to 2 weeks! How? They empowered the staff to make decisions, involved them in decision making (not lip service involvement, but real input) and organised them into a team environment rather than the Taylorist/Fordist Scientific management principles of production lines.
Where people feel a disconnect from the manufacturing work process, you are more likely to find a union presence. I don't know so much about gov't, or office worker unionism.
Where do I stand? At least in this country, we have adequate legislative tools in place to protect workers. So, no to unions so long as the relevant authorities investigate and prosecute those that take advantage of employees.
RS