regardless of right to work, all govt agencies are unionized, teachers etc. so even if you're a Right To Work State, you are still dealing with unions as a state employer.

I believe companies ALREADY have this right.

Someone correct me if I'm wrong - but my understanding of the situation is:

a) If a company is union, they have basically signed away their right to shop for employees on the open market. They have agreed they will only buy labor from the union. But they gave up that right voluntarily.
b) Once the union contact has expired, the company CAN choose to not renew the contract. The practical problem is this means they have to instantly hire an entire replacement workforce.

Do I have this right, or am I wrong?

In Michigan we just passed "right to work" to the dismay of unions. In fact, unions sent a thug to a rally in favor of right to work and the thug beat up a reporter. Hmmm, something about Rearden Steel comes to mind.
Right to work is a good thing. If someone wants to be in a union no problem - but the employer is not forced to deduct union dues automatically from an employees paycheck. This cuts off the money stream to unions and requires unions to have a product to sell. The contradiction is that a professional oraganization cannot set fees for their members - this is antitrust, but unions can strike for wages. My friends that are in unions cannot see beyond their nose and have no clue about running a business. As Michigan becomes more attractive to manufacturers the unemployeed will sing a different tune- that is if they will come off of welfare and unemployment benefits.

The problem here is that the unions are so powerful, and have the unbridled support of our pres, that they use use intimidation tactics against companies that want to stay union free. Or if you don't want to join a union in a unionized co, you are threatened, overtly or covertly, it doesn't matter. I find them to be completely unnecessary now, because there are already so many protections for employees, and all the unions do is collect dues for corrupt bosses. It's such a scam!!

Companies also MUST display posters promoting unions, even if they are non union. So even if you don't want them, and your employees don't want them, they insinuate themselves into the company.