This story is part of, CNET's coverage of the voting in November and its aftermath.
A group of senior Democratic senators is requesting that the Department of Homeland Security publish its analysis of foreign disinformation campaigns that are trying to undermine confidence in voting by mail. The briefing, provided to lawmakers on Sept. 3, highlights that remarks made as part of these campaigns align closely with President Donald Trump's attacks on mail-in voting, according to the lawmakers.
Senate Intelligence committee Vice Chairman Mark Warner, committee member Ron Wyden, Senate Democratic leader Chuck Schumer, Rules committee ranking member Amy Klobuchar and Homeland Security committee member Gary Peters signed a letter sent to acting DHS Secretary Chad Wolf on Thursday.
The intelligence community hasn't found any evidence of vote-by-mail fraud, but Trump and members of his administration, such as Attorney General William Barr, have repeatedly claimed that mail-in voting is rampant with fraud. Social networks have frequently marked Trump's statements about vote-by-mail as misleading.
On Tuesday, during the first presidential debate, Trump made more false claims about mail-in ballots, and national security officials said those claims have been used to spread disinformation online.
Millions of Americans are expected to vote by mail this election because of, which as of October has killed more than 200,000 people in the US. COVID-19, the contagious disease caused by the virus, is leading people to vote from the safety of their homes, and several states have started automatically sending ballots to registered voters.
Election security specialists say vote-by-mail is a secure process with rare occurrences of fraud, and that most mix-ups that do occur are often mistakes, rather than coordinated campaigns. During a press briefing Aug. 26, the FBI said it would be "extraordinarily difficult to change a federal election outcome" through mail-in fraud.
Though it's difficult to commit mail-in voting fraud, it's not hard to spread disinformation about vote-by-mail. And convincing people that election results are questionable can have a similar effect to actually rigging a vote.
Nation-state actors from Russia, Iran and China are looking to interfere with the 2020 presidential election and are using the same playbook as the Trump administration, according to the DHS' analysis from Sept. 3, the lawmakers said.
"This document demonstrates that a foreign actor is attempting to undermine faith in the U.S. electoral system, particularly vote-by-mail systems, in a manner that is consistent with the rhetoric being used by President Trump, Attorney General Barr, and others," reads the senators' letter to the DHS.
The senators want the analysis made public, noting that it's already marked unclassified and wouldn't create a national security risk if released.
The DHS didn't respond to a request for comment.
"It is now critical and urgent that the American people have access to this document so that they can understand the context of Trump's statements and actions," the letter says.