You do not have free speech at work.

All the constitution says is that the GOVERNMENT may make no law abridging free speech. Companies, people, etc. are free to limit speech.

The company can fire someone for any reason at any time or for no reason.

Once union activities have begun, there are some protection but very little.

In your example, who are we kidding? — they aren’t really asking for your personal opinion. They want a pro-union statement from a management person they can use for leverage.

And yes, you could be fired over that. When you are engaged in company business, the company has a right to expect you to advance the company’s goals. This is no different than salesman who, if asked, says that personally he prefers the competitor’s product. Would you fire that salesman? Yes!!!

If you are pro-union, then your recourse is to work for a company which does not oppose unions. You can’t take this company’s money and expect them to tolerate you undermining their goals.

Edited to add: Regarding the free speech issue, there is a big difference between a person’s right to free speech, and an employer’s obligation to provide a platform for that right. The employer has no such obligation. Free speech means the government won’t limit what you say, not that you get to keep your job no matter what you say.

Technically, a company is not allowed to fire anyone for anything they do or say off the clock and away from their property (local laws may vary). In practice, however, a company can fire anyone for almsot anything, it’s not that hard to come up with a legally sound justification.

The balance of free speech and and anti-union is in the same boat. By the letter of the constitution, it is actually illegal for the company to order managers to oppose union talk or meetings. But the practical side of things is that you have to walk the line of what you’re individual company will tolerate in your specific situation, because they have better lawyers than you can afford, especially once they fire you.

I don’t know if the guy can be fired or not. That’s a grey area but he should be fired. If the manager does not feel that he can support his company and its policies wholeheartedly, he should get another job.
If it were my company and I learned that he does not support our policies and believe in them, he’d be looking for a job.
If it was illegal to fire him ( and I’m certain that it’s not) I’d find some other reason to get rid of him fairly soon.

Ummm… the union would be very interested to hear that you have been issued orders to oppose. Most collective agreements state that union activities should not be held on company time but that the union and management will work together, not fight. As a manager you should seek advice from HR professionals, etc. to ensure you are following the spirit as well as the letter of any existing collective agreements. And you should be allowed to support and respect unions in private, the company does not own your private political leanings or thoughts.