Republican presidential candidate Donald Trump waves to the crowd during a campaign rally on Oct. 13 in Cincinnati. (John Minchillo/AP)

Former senior U.S. national security officials are dismayed at Republican presidential candidate Donald Trump’s repeated refusal to accept the judgment of intelligence professionals that Russia stole files from the Democratic National Committee computers in an effort to influence the U.S. election.

The former officials, who have served presidents in both parties, say they were bewildered when Trump cast doubt on Russia’s role after receiving a classified briefing on the subject and again after an unusually blunt statement from U.S. agencies saying they were “confident” that Moscow had orchestrated the attacks.

“It defies logic,” retired Gen. Michael V. Hayden, former director of the CIA and the National Security Agency, said of Trump’s pronouncements.

Trump has assured supporters that, if elected, he would surround himself with experts on defense and foreign affairs, where he has little experience. But when it comes to Russia, he has made it clear that he is not listening to intelligence officials, the former officials said.

“He seems to ignore their advice,” Hayden said. “Why would you assume this would change when he is in office?”

Russian president Vladimir Putin says the scandal that has erupted in the United States over allegations Russia hacked Democratic Party emails has not been in Moscow's interests and that both sides in the U.S. election campaign are just using Russia to score points. (Reuters)

The Trump campaign did not respond to requests for comment.

Several former intelligence officials interviewed this week believe that Trump is either willfully disputing intelligence assessments, has a blind spot on Russia, or perhaps doesn’t understand the nonpartisan traditions and approach of intelligence professionals.

In the first debate, after intelligence and congressional officials were quoted saying that Russia almost certainly broke into the DNC computers, Trump said: “I don’t think anybody knows it was Russia that broke into the DNC. I mean, it could be Russia, but it could also be China. It could also be lots of other people. It also could be somebody sitting on their bed that weighs 400 pounds, okay?”

During the second presidential debate, Trump ignored what a U.S. government official said the candidate learned in a private intelligence briefing: that government officials were certain Russia hacked the DNC. That conclusion was followed by a public and unequivocal announcement by the Office of the Director of National Intelligence and the Department of Homeland Security that Russia was to blame.

“Maybe there is no hacking,” Trump said during that debate.

“I don’t recall a previous candidate saying they didn’t believe” the information from an intelligence briefing, said John Rizzo, a former CIA lawyer who served under seven presidents and became the agency’s acting general counsel. “These are career people. They aren’t administration officials. What does that do to their morale and credibility?”

Former acting CIA director John McLaughlin said all previous candidates took the briefings to heart.

“In my experience, candidates have taken into account the information they have received and modulated their comments,” he said. Trump, on the other hand, “is playing politics. He’s trying to diminish the impression people have that [a Russian hack of the DNC] somehow helps his cause.”

On Thursday, the ranking Democrat on the Senate Intelligence Committee, Sen. Dianne Feinstein (Calif.), said information she received has led her to conclude that Russia is attempting “to fix this election.” She called on Trump and elected officials from both parties “to vocally and forcefully reject these efforts.”

Trump has consistently adopted positions likely to find favor with the Kremlin. He has, for instance, criticized NATO allies for not paying their fair share and defended Russian President Vladi­mir Putin’s human rights record.

“It’s remarkable that he’s refused to say an unkind syllable about Vladimir Putin,” Hayden said. “He contorts himself not to criticize Putin.”

Trump’s running mate, Indiana Gov. Mike Pence, said in the vice-presidential debate last week that the United States should “use military force” against the Syrian leader Bashar al-Assad.

Trump disagreed. Rather than challenge Assad and his Russian ally, Trump said in the second debate, the United States should be working with them against the Islamic State. “Assad is killing ISIS. Russia is killing ISIS. Iran is killing ISIS,” he said, using an acronym for the Islamic State. Russia and Syria have mostly been targeting opposition groups as well as civilians trapped in Aleppo — not the Islamic State.

“That’s the Syrian, Russia, Iranian narrative,” Hayden said of Trump’s assertion.

Greg Miller contributed to this report.