Democratic National Committee chair Tom Perez asked his Republican counterpart, Republican National Committee chair Ronna McDaniel, to promise that Republicans will not "encourage theft of private data" or use information from stolen data in campaigns. Perez's request, published in an open letter on Medium Monday, came days after special counsel Robert Mueller's report confirmed Russian interference in the 2016 election through hacking and disruptive social media campaigns.

"As the leaders of our country's two largest political parties, we have a responsibility to protect the integrity of our democratic process," Perez wrote to McDaniel. "That's why I urge you to join me in condemning the weaponization of stolen private data in our electoral process."

Perez alluded to Mueller's conclusion that "that the [Trump] Campaign expected it would benefit electorally from information stolen and released through Russian efforts," although no member of the campaign directly conspired with Russia in 2016. Perez said the report "describes a Trump campaign that gleefully sought to benefit from that attack."

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"As you know, President Trump himself openly called for Russia to steal and spread his opponent's data. These are not the actions of a candidate or a party that respects the rule of law or the integrity of our democracy," Perez wrote, referring to President Trump's invitation to Russia to hack his opponent Hillary Clinton's emails in the summer of 2016. He also noted that Mr. Trump's personal lawyer, Rudy Giuliani, said Sunday "there's nothing wrong with taking information from Russians."

Perez also wrote that McDaniel's predecessor as chair of the National Republican Committee, Reince Priebus, who later became Mr. Trump's first chief of staff, did not respond to Democrats' request in 2016 that Republicans not rely on stolen data in the campaign.

"Under my leadership, the Democratic National Committee will not encourage the theft of private data, nor will we seek out or weaponize stolen private data for political gain," Perez wrote, adding that this was not an issue of "red and blue" but of "red, white and blue."

"I'm calling on you to put country above party and publicly pledge that the Republican National Committee will do the same," he added.

A spokeswoman for the RNC said that McDaniel has previously addressed this issue and made it clear that it is important to "safeguard" future elections.

"Any breach of our political organizations - regardless of party - is an affront to all of us, and we should come together as Americans to prevent it from ever happening again. It's important we do all we can to safeguard our future elections," McDaniel said in a statement.

Sen. Kirsten Gillibrand broadcast a similar message on Monday evening, becoming the first Democratic presidential candidate to pledge that she will not "seek, use or weaponize stolen hacked materials" in her campaign.

"Russia is a foreign adversary of the United States, and we all must learn serious lessons from their cyber attack on our election systems in 2016. Russia will be back, and it is troubling that President Trump and his top aides are not only failing to hold them accountable but actually normalizing the idea of 'taking information from Russians' for political gain," Gillibrand said in a statement, also referring to Giuliani's Sunday comments.

"For my part, I vow that our campaign will not seek out stolen hacked information from foreign adversaries or knowingly weaponize such materials, and I urge my colleagues in the 2020 field to join in signing this pledge. Together we can send a clear message to those who seek to harm our democracy - at home and abroad," she added.