Hillary Clinton’s presidential campaign has found ways to coordinate with a deep-pocketed Super PAC despite legal restrictions on its work with third party political groups that can raise unlimited sums from unions and corporations, internal documents reveal.

Campaign staffers have discussed sharing fundraising information with Priorities USA, the most prominent Super PAC on the Democratic side, courting potential Priorities donors, and having Clinton personally thank high-dollar contributors, according to emails to and from campaign chairman John Podesta and another campaign staffer.

Most of the emails were posted on the website Wikileaks after hackers breached Podesta’s personal email account. U.S. intelligence and law enforcement agencies believe that the hackers responsible for the breach are taking directions from high-level Russian government officials.

The emails and documents attached to them show that the Clinton campaign has been careful to stay within the bounds of the law while maximizing their behind-the-scenes work with Priorities.

The Super PAC has spent more than $130 million supporting Clinton and other Democratic candidates this cycle. Its roster of supporters includes some of the country’s biggest Democratic donors, including George Soros, Jim Simons, Fred Eychaner, Donald Sussman, Haim Saban, and Daniel Abraham.

Super PACs can raise and spend unlimited funds from individuals, corporations, and labor unions, but are generally prohibited from coordinating with candidates and their campaigns.

However, in an internal campaign memo a week after Clinton officially launched her candidacy, campaign general counsel Marc Elias briefed senior staff on the ways in which they could legally complement Priorities USA’s fundraising and communications operations.

According to Elias, Hillary for America, Clinton’s campaign committee, is legally permitted to advise Priorities on which donors to ask for money, how much those donors might give, and to strategize on messages to use when making those solicitations.

In order to comply with the subtleties of campaign finance laws, Elias recommended keeping language vague.

"Donor A works in financial services and has been a long-time contributor. I think she’d be willing to do six figures for Priorities," is fine, he wrote. "I want you to call Donor A and ask for $250,000" is not.

As the campaign provides fundraising input, Priorities can give regular updates regarding its fundraising progress. "It would be permissible for Priorities to disclose its total funds raised and its cash on hand in a written memo to HFA delivered on regular intervals," Elias wrote.

Clinton and her campaign staff can also raise money for Priorities USA directly, Elias wrote, as long as they ask for only $5,000, the legal maximum for donors to traditional political action committees. The Federal Election Commission has ruled that such solicitations from candidates and their staffs are legally permissible.

Priorities confers membership for its top donors in what it calls a "presidential club." According to Elias, Clinton and her staff can thank those top-dollar donors after the fact for supporting the group.

When Clinton attended a February fundraising event at the Chicago home of wealthy Democrat J.B. Pritzker, fundraising staffers recommended that she "thank J.B. for his generous support of Priorities USA," according to an internal memo released by hackers who breached the account of a campaign volunteer.

Pritzker has donated more than $5 million to Priorities USA.

The campaign discussed engaging with another high-dollar Democratic donor to finance the group in a May 2015 email. When Podesta met privately with Chicago media mogul Fred Eychaner that month, Podesta’s assistant noted that the campaign "would like to engage Fred on Priorities USA down the road."

Eychaner has donated $8 million to the group since then.

On the day of Podesta’s meeting with Eychaner, senior Clinton campaign staffers were scrambling to respond to a forthcoming New York Times story revealing that Clinton was attending Priorities USA events.

"We have NOT confirmed the meeting and will not be confirming these types of meetings," wrote Clinton spokesman Jesse Ferguson after the Times reached out to the campaign.

Ferguson provided talking points for other campaign staffers to share with reporters on "deep background (Clinton official/no quote)." They noted that Obama had also worked with Priorities, as legally permissible, during the 2012 campaign.

"Campaign officials, including the candidate may, from time to time, attend, speak at or be featured guests at their events," another talking point noted.

Clinton staffers were not happy that news of the candidate’s events had become public. Campaign spokeswoman Jennifer Palmieri suspected that someone at the Super PAC was responsible for the leak.

"Honestly, it sounds like Priorities staff was yapping," Palmieri wrote.

The Clinton campaign did not respond to a request for comment.