First, I am no longer a Democratic elected official, but I was.
Labor unions are an important balance to the problem of too-dominant management in the workplace. But the question of destroying the basic democracy of a free ballot does not convince me. If the ballot is equally secret to the union and the management, then it is the workers who win.
Getting the secret balot was one of the basic building blocks of democracy. Disagreement from the Nazis and Stalinists is normal on this point. What would they have done with "card check" instead of elections?