If unions want the proxies of their pension fund holdings voted in a particular way, they should take the responsibility for voting them.
An AFL-CIO survey found some money management firms have consistently voted proxies against union corporate governance positions, and union officials have expressed disappointment. Further, the officials plan to pressure the managers to change.
Far better that the unions take the proxy voting responsibility from the managers. Then they can be sure the proxies are voted according to their wishes. As it is, pressuring the managers to vote the proxies in accordance with union corporate governance policies could put the managers in untenable positions.
The managers, who should seriously study the long-term impact on the affected company of every proxy vote, might have determined the unions' position is not in the best interests of the majority of shareholders. (The unions might not agree, but such is possible.)
Any manager who succumbed to union pressure on voting proxies after reaching such a determination would be violating fiduciary duty to all shareholders.
From the union viewpoint, taking back the proxy responsibility might not be the best solution for several reasons. First, they have to take the responsibility. Second, they have to do the homework and clerical work (or hire an outside proxy-voting service, which costs money). Third, they may not be able to pressure the managers to vote other clients' proxies in the pro-union manner.
But managers, as long as they have the responsibility for voting the proxies, must vote them in their best analysis of the long-term interests of all shareholders. If that analysis leads to a position contrary to the union position, so be it.