This weekend voters in Massachusetts were exposed to the first negative TV attack ad of the still young 2014 state election season. The ad was paid for by the state independent expenditure PAC (i.e. Super PAC) of the National Association of Government Employees, a national union affiliated with SEIU.

We know this because of a Massachusetts “stand by your ad” law that requires political groups to clearly identify themselves in television advertisements. And we will soon know the cost of the ad and the vendors paid to produce it because of other campaign finance disclosure rules.

But what we won’t know for quite some time is who contributed the money to pay for the ad in the first place. Current disclosure laws only require Super PACs to disclose donors eight days before the primary election and once more eight days before the general election. That means voters will remain largely in the dark as to who is funding NAGE and the more than two dozen other Super PACs currently registered with the Office of Campaign and Political Finance (OCPF) until just before the election.

Admittedly, this is less of an issue with union backed Super PACs like NAGE that have a clear public history and are usually funded by union member dues. That being said, voters deserve to know the names of contributors and the size of contributions.

Full disclosure is all the more important when the group has an innocuous name and no public history, but springs up out of thin air to support a specific candidate in a specific race and then dissolves just as quickly as it was formed. This problem of transparency was poignantly exposed by the One Boston Super PAC which dropped a $500,000 ad buy in the week before the 2013 Boston mayoral election. On Election Day, the public and mayoral candidates had no idea which interests were supporting One Boston. More than a month after all the votes had been tallied did media reports finally reveal that One Boston was a subsidiary of the American Federation of Teachers. Current campaign finance filings still list the sole donor of One Boston as One New Jersey.

A similar saga could play out in the high stakes Massachusetts governor’s race. To date, Super PACs with names as vague as Massachusetts Forward Together, Commonwealth Future, et Mass Independent are gearing up to influence our election. Which individuals and special interests are funding these groups? Voters won’t know until the first week of September.

It doesn’t have to be this way. The legislature could act today to require real time disclosure of Super PAC donors and expenditures and close other loopholes in the law (for example, if a group doesn’t organize as a Super PAC, it may be able to bypass donor disclosure altogether, and corporations are not required to disclose independent expenditures). A widely popular bill to do just that is pending in the Elections Laws Committee now. The bill would also require disclosure of a Super PACs top five contributors in paid advertisements. In 2012, the Massachusetts Senate unanimously passed a similar disclosure bill.

But time is quickly running out to enact this important reform before political ads start flooding the airwaves. If you haven’t done so already, tell your state legislators to take immediate action to ensure transparency in our elections.