WASHINGTON — Nancy Pelosi, the House minority leader, sent a letter on Tuesday to Speaker Paul D. Ryan urging him to bar Republicans from using hacked documents in the campaign, arguing that “defending our democracy is more important than any advantage or disadvantage in this election.”
Ms. Pelosi, calling the hack into Democratic servers, apparently by Russians, “an unprecedented assault on the sanctity of our democratic process,” said Mr. Ryan should not condone either party using materials originating from the cybercrime.
“Democrats and Republicans must present a united front in the face of Russia’s attempts to tamper with the will of the American people,” Ms. Pelosi wrote.
Government officials have concluded that two Russian intelligence agencies, the F.S.B. and the G.R.U., are responsible for the hacking into theDemocratic National Committee and the House Democratic campaign arm. Emails and other internal documents have been published by a hacker calling himself Guccifer 2.0, who is believed to be tied to the Russian intelligence agencies.
Mr. Ryan’s aides referred questions about Ms. Pelosi’s request to the House Republican campaign arm, the National Republican Congressional Committee. A spokeswoman for the committee did not rule out using hacked content, but disclaimed responsibility for the one instance it had happened thus far.
“Neither the N.R.C.C.’s chairman, Greg Walden, nor the speaker have control over what our independent expenditure unit does, which the D.C.C.C. chairman, Ben Ray Lujan, as well as Leader Pelosi are well aware of,” said the spokeswoman, Katie Martin, referring to the Democratic Congressional Campaign Committee.
To date, the only hacked documents to surface have come from the internal servers of Democratic committees, an indication that only one of America’s two major political parties is being targeted. Already, the hacks revealed that the Democratic National Committee favored Hillary Clinton and discussed ways to undermine Senator Bernie Sanders of Vermont in its presidential primary, disclosures that led to the resignation of the party chairwoman, Representative Debbie Wasserman Schultz.
While alarmed at what is being exposed, Democrats also sense an opportunity to use the cybercrime to link Republicans to President Vladimir V. Putin of Russia. It is a task that has been made easier by the Republican presidential nominee, Donald J. Trump, who has frequently praised Mr. Putin, called to improve relations with Moscow and urged Mr. Putin’s government to hack into Mrs. Clinton’s emails.
On Monday night, Mrs. Clinton told reporters that Russia’s intrusion represented “a threat from an adversarial foreign power,” and cited “credible reports about Russian interference in our elections.”
And last week, Harry Reid of Nevada, the Senate Democratic leader, went even further, sending a letter to the F.B.I. director, James B. Comey, urging him to investigate Russian interference that “may include the intent to falsify official election results.”
By asking Mr. Ryan to effectively declare hacked documents politically off limits, Ms. Pelosi is attempting to force him to choose between being seen as abetting the cybercrime of a hostile power and leaving potentially fruitful material unused. House Republicans have already seized on one of the hacked documents, releasing a digital ad last month that cited a House Democratic memo posted by Guccifer 2.0 that outlined the potential vulnerabilities of a Democratic candidate in Florida.
The posting of House Democratic documents relating to the Florida races was apparently meant to correspond to the state’s primaries last week. While no Republican leaders have pledged not to use hacked materials, Reince Priebus, the chairman of the Republican National Committee, recently said that the hack was “not right” and that he was “not on board with whatever they did to steal this information.”
For his part, Mr. Putin has denied that his government was responsible for the hacking but has made no effort to conceal his pleasure about the disclosures.
“Listen, does it even matter who hacked this data?” Mr. Putin said in a Bloomberg News interview last week. “The important thing is the content that was given to the public.”