[lumberjack]

Neither Obama nor Clinton are sponsored by unions. Their major sponsors are Wall St, universities, SV and Hollywood, i.e. typical wealthy democrats.

http://www.opensecrets.org/PRES08/contrib.php?cid=N00009638

Maybe you were thinking about Bernie Sanders?

[MarcusVorenus]

Unions don't donate directly, they make independent campaign expenditures through Super PACs. Look in the Independent Expenditures tab in the page you gave me.