Not really. Obama's foreign policy is better than the republicans and he genuinely cares about people so healthcare and welfare policies would be better, but his support base also consists of the unions, which I disagree with.
They're not the same. Unions are equivalent to crony capitalism (ie. regulations put in place to prevent competition), but most of what companies do is just free markets at work (which helps the consumer).
In what country? In the US, most are mandated by law. All government jobs are union, regardless of the wishes of the worker.
Contracts are mutually consented to. If it's a union job, you have to be a part of the union. How is forcing workers to do something they do not want beneficial?
I'm all for unions where someone can join and leave freely without the threat of force or loss of work. Do we have that in the US? No.
I'm not sure that is correct. If you look here[1], at the federal level it's about 31%. I also know of several teachers who are not in a Union.
As far as Union jobs go, it depends. There are Union jobs that require it and don't require it. However, this has nothing to do with the worker, but is actually a contractual obligation that the employer agreed to.