I'm getting this from Jane Hamsher's blogpost on HuffPo, but the data really comes from the National Journal (subscriber only).
[Diane Feinstein's] proposal would replace the card-check provision, which would allow workers to unionize if a majority signed authorization cards and strip a company's ability to demand a secret ballot election. "It's a secret ballot that would be mailed in ... just like an absentee ballot. The individual could take it home and mail it in," Feinstein said. If a majority mailed the ballots to the National Labor Relations Board, the NLRB would recognize the union.
...and I did mention the part where Diane Feinstein wants to be Governor of Union heavy California, right?? Being the one to stop EFCA's passage is a good way to make sure you don't become Governor.