The Federal Election Commission is deadlocked on whether to exempt mobile ads from the disclaimers that appear by law on political messaging — throwing a wrench in the plans of a left-leaning communications firm and pitting its strategists against the FEC's Democratic appointees.

The firm in question is Revolution Messaging, whose clients include MoveOn.org, Organizing for America and various Democratic committees. Last fall, Revolution asked the FEC for permission to eliminate disclaimers from its digital banner ads, arguing that the small screens on mobile devices made it impractical to include the legalese. Republican officials sided with Revolution, saying that a disclaimer was unnecessary; Democratic commissioners disagreed.

A second, softer proposal had Revolution committing to shortened disclaimers. According to head of digital advertising Keegan Goudiss, "a couple of Democratic commissioners seemed open" to the idea. But on Thursday, those officials voted against it, resulting in an inconclusive 3-3 split on the panel. (Four votes are required to approve a measure.)

"Mobile phone advertisements, which may be disseminated on a national scale to voters, are clearly general public political advertising and do not warrant special exemption from disclaimer requirement," several of the commissioners wrote in a statement.

In an interview, Goudiss said the decision — or lack thereof — will limit Revolution Messaging's options.

"There are certain things we want to do, like put vote reminders on people's calendars, that we won't be able to do," he said, "because vendors will say, 'There's not enough to cover us here.'"

The FEC offers a selective exemption for "small items" like buttons and bumper stickers that don't provide the space for a disclaimer. There's also an impracticality exemption for skywriting and other forms of large, public messaging.

But political advertisers could easily accommodate the limitations of a small banner ad, the FEC suggested. Strategists might consider taking out larger ads, it said, or they could link ads to a separate landing page with the required disclaimer.

This isn't the first time the FEC has struggled to rule on technological campaign elements. In 2010, the commission split on whether to require Google to attach disclaimers to political ads generated in search results. Despite not reaching a consensus in that vote, either, the commission said informally that omitting the disclaimers was not against the law.