A Republican plan to hold the party’s 2016 national convention a month early will let its nominee tap into general election money early — and potentially increase the time outside groups have to run “dark money” ads backing that nominee that don’t have to be disclosed.

Election law prohibits a presidential candidates from using general election funds until after the national convention. That pesky firewall accounted for Mitt Romney’s campaign borrowing $20 million that it already had, but could not legally spend before he was officially the Republican nominee for president.

The RNC press release notes the move will allow “access to crucial general election funds earlier than ever before to give our nominee a strong advantage heading into Election Day.” But what’s not mentioned is the repercussions for outside groups planning to run ads in 2016; namely, a longer window to run ads with no disclosure between the convention and the general election.

That’s due to a quirk in campaign finance law. All political ads that name a presidential candidate and run 30 days or less before the convention must be reported to the Federal Election Commission — even if the ads stop short of urging people to vote for or against a candidate.

The Washington Post reports that Democrats are likely to follow suit in moving up their convention time table — and may also hold their nominating convention in July.

It’s not totally clear what would happen if the Democrats don’t hold their convention in roughly the same time frame. One possibility of an early GOP convention and a late Democratic convention might be that issue ads running in between the two conventions might only have to be disclosed if they named Democrats.

Campaign reformers have sought to lengthen the “electioneering window” during which these ads must be reported. The DISCLOSE Act — which Sunlight supported — would have begun this period 120 days before any election.

Dark money groups have long run “issue ads” slamming their opponents in order to fly under the radar. While a series of court decisions now known as Citizens United has made it perfectly legal for these groups to run ads that do call on voters to back particular candidates, it’s often in these groups’ interest not to do so.

For one, political nonprofits that don’t report their donors must be able to claim that their “primary purpose” isn’t political. That’s been widely interpreted to mean that less than half their budget is spent on ads clearly backing a candidate. But issue ads can be reported as part of a group’s educational mission.

Moreover, issue ads that run more than thirty days before the nominating convention, or 60 days before a general election (or 30 days before a primary election) don’t have to be reported to the Federal Election Commission at all. So it’s nearly impossible for watchdogs to calculate just how much a dark money group is really spending on political ads.

Under the current campaign finance regime, outside groups have taken the lead in advertising long ahead of the election. That allows the candidates to save their money until the final days of the election, when they are guaranteed the lowest possible rate on TV ads.