Unconstitutional on 14th amendment grounds and first amendment grounds.
They are privileging speech rights from some groups over other groups (unions v corps).
They are privileging speech rights from some groups over other groups (unions v corps).
The people making up the corporation can all vote as individuals and the corporation itself has no vote. This is no different.
They are however, groups of individuals.
Should we give corporations the right to vote? Should its members would have double voting rights?
In general, shareholders are always able to pool their money directly in the manner you are stating. This being uncommon shows that the situations are not equivalent.