Carlos Barria / Reuters Russian President Vladimir Putin, third from left, sits next to President Donald Trump at a G20 summit meeting in Germany on July 7. An ABC News/Washington Post poll found that 66 percent of Americans are mistrustful of Trump negotiating with Putin.

WASHINGTON – Having told falsehood after falsehood about everything from inaugural crowds to FBI Director James Comey’s firing, why would anyone believe a single word coming from this White House?

That’s the fundamental problem a beleaguered communications team faces as it tries to respond to claims that Donald Trump’s campaign colluded with Russia to help win the presidency last year, with the public appearing to settle into the view that White House statements simply cannot always be taken as fact.

“Credibility may be repairable around the margins ― if, for example, someone misspeaks,” said Ned Price, a former CIA analyst and spokesman for former President Barack Obama’s National Security Council. “But there’s a point of no return after which credibility will always be tarnished. The White House passed that point long ago.”

An email released last week showing that Donald Trump Jr. not only knew the Russian government was helping his father but also that Trump’s eldest son actively encouraged it came after a full year of candidate Trump and his campaign team initially denying any contact with Russians, let alone collusion.

“If it’s what you say I love it,” Trump’s eldest son wrote just minutes after receiving the June 2016 email from a business associate offering “very high level and sensitive information but is part of Russia and its government’s support for Mr. Trump.”

President Trump, as he has for days, again tried to defend himself and his son on the issue with a Monday morning statement on Twitter: “Most politicians would have gone to a meeting like the one Don jr attended in order to get info on an opponent. That’s politics!”

Most politicians would have gone to a meeting like the one Don jr attended in order to get info on an opponent. That's politics! — Donald J. Trump (@realDonaldTrump) July 17, 2017

That was followed hours later by press secretary Sean Spicer claiming in the daily White House press briefing: “There was nothing, as far as we know, that would lead anyone to believe that there was anything except for a discussion about adoption and the Magnitsky Act.”

The narrative of the “adoption” agenda was crafted by top White House staff as they flew back from Germany on July 8 ― even though they knew that the email was offering negative information about presidential rival Hillary Clinton and didn’t mention adoption or the Magnitsky Act, which had imposed sanctions on Russians.

The White House press office did not respond to queries about the Trump White House’s pattern of false statements, and Spicer did not respond to a request for clarification about Monday’s adoption claim from the White House lectern.

What Spicer or anyone in the press office could do at this point to regain credibility is unclear. Spicer’s aggressive insistence on provably untrue assertions began the day after the Jan. 20 inauguration, when he told reporters in the White House briefing room that the crowd attending Trump’s inaugural was the largest ever ― even though photographs clearly showed it was a fraction of the size of Obama’s inauguration in 2009.

Trump had the lowest percentage of truthful statements of any recent presidential candidate, according to the fact-checking group PolitiFact. Of the more than 400 Trump claims the group has analyzed since he entered the race in 2015 through his first six months in office, a full 69 percent are rated “mostly false,” “false” or “pants on fire.”

A new poll shows that the repeated dishonesties appear to have taken their toll on the Russia issue.

In an ABC News/Washington Post survey released Sunday, 63 percent of respondents said the meeting Trump Jr. had with a Russian lawyer and a former Russian spy, among others, at Trump Tower in June 2016 was inappropriate, compared with 26 percent who did not see a problem. That meeting also included Jared Kushner, the president’s son-in-law and now a top White House adviser, and Paul Manafort, who was then chairman of the Trump campaign.

A full 66 percent of Americans are mistrustful of Trump negotiating with Russian leader Vladimir Putin, while only 32 percent trust he would do a good job.

More broadly, only 36 percent of Americans approve of the job Trump is doing as president, a 6-percentage-point drop from what that poll found three months ago. “Lies/false statements/dishonest” was tied for second among the characteristics that Americans most disliked in Trump, according to the poll results. “Inappropriate way he talks and acts” and “everything” were tied for first.

Mike McCurry, a press secretary in the Bill Clinton White House, said Clinton was able to bounce back after being caught lying about his sexual involvement with an intern by, in part, focusing on his work.

“When faced with a tough crisis about things personal, President Clinton over and over said that he would get back to his job as president,” said McCurry, now a theology professor at Wesley Theological Seminary in Washington, D.C. “And he did. And the results were pretty good, and the American people were very forgiving. That’s the best lesson this White House should take away.”

Whether Trump or his White House staff is capable of that, McCurry said, is an open question. “An ironclad commitment to telling the truth would be helpful, but I am not sure how you would get this team to commit to that responsibility.”