FILE - This Thursday, April 18, 2019 file photo shows special counsel Robert Mueller's redacted report on Russian interference in the 2016 presidential election as released in Washington. An Associated Press review shows the idea of Ukrainian interference took root during Donald Trump’s 2016 presidential campaign, was spread online and then amplified by Putin before some of America’s elected officials made it their truth. (AP Photo/Jon Elswick)
FILE - This Thursday, April 18, 2019 file photo shows special counsel Robert Mueller's redacted report on Russian interference in the 2016 presidential election as released in Washington. An Associated Press review shows the idea of Ukrainian interference took root during Donald Trump’s 2016 presidential campaign, was spread online and then amplified by Putin before some of America’s elected officials made it their truth. (AP Photo/Jon Elswick) Credit: Jon Elswick

The theory took root in vague form well before Donald Trump laid claim to the White House in 2016. The candidate’s close confidant tweeted about it. His campaign chairman apparently spoke about it with people close to him.

What if, the idea went, it was actually Ukraine — and not Russia — that was interfering in the 2016 election?

Never mind that the notion has since been amplified by the president of Russia, the country that U.S. intelligence agencies unequivocally blame for interfering in that year’s presidential race. Or that Trump’s hand-picked FBI director and other American officials have said there’s no information pointing to Ukraine interference. Or that 25 Russians stand charged in U.S. courts with hacking into Democratic emails and waging a covert social media campaign to sway American public opinion.

The Ukraine theory lives on.

Now, Trump’s request for Ukraine to investigate the matter and a political rival, former Vice President Joe Biden, is at the heart of a congressional inquiry that produced Trump’s impeachment by the House of Representatives. A Senate trial is next.

The discredited theory, spread online by GOP allies in interviews and tweets, has been embraced by a president reluctant to acknowledge the reality of Russian election interference, and anxious to show he had reason to be suspicious of Ukraine as the U.S. withheld crucial military aid last year.

The effect: blurring the facts of the impeachment case for many Americans even before it reaches a trial that could begin with days.

Experts fear the strategy leaves the U.S. vulnerable to more misinformation campaigns in the 2020 election and signals to the Kremlin and other foreign actors that Americans are willing to cling to falsehoods.

A review by the Associated Press shows that the Ukraine conspiracy theory traces back to Trump’s 2016 campaign, was spread online and later advanced by Russian President Vladimir Putin weeks after his own country was blamed for election interference. Finally, some of America’s own elected leaders made it their truth.

As U.S. authorities collected evidence in 2016 that Russia had hacked and stolen years of internal emails from the Democratic National Committee, Trump campaign chairman Paul Manafort, who had cultivated extensive business contacts in Ukraine and worked for pro-Russia politicians there, was privately pointing to another culprit.

Manafort, now serving more than seven years in prison for tax fraud and other crimes, suggested then that the attack was probably executed by Ukrainians, according to FBI notes from an April 2018 interview with Rick Gates, Manafort’s former deputy. The idea parroted that of Konstantin Kilimnik, a Manafort business associate who U.S. authorities have assessed has ties to Russian intelligence – an accusation Kilimnik has denied.

Trump aide Michael Flynn, who later became Trump’s first national security adviser, was also adamant within the campaign that Russia couldn’t have carried out the attack and that U.S. intelligence wouldn’t be able to figure out who had done it, Gates recalled.

That skepticism was adopted by Trump himself, who memorably said during a presidential debate that “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, OK?”

All the while, U.S. officials were agreeing with a private cybersecurity firm’s findings that Russia was responsible, collecting evidence over the next several months that tied individual Russian military intelligence officers to the hack.

As the Democrats’ stolen emails were published online and the U.S. prepared to publicly blame the Kremlin for the hack, assertions surfaced online that Ukraine had meddled – directly or indirectly – in America’s presidential campaign.

Dozens of news outlets debunked Trump’s comments and continue to do so. Finding itself at the center of the phone call, CrowdStrike then released a blog post rebuffing the president’s claims. The president’s own national security advisers rebutted the theory to no avail, former White House aide Fiona Hill told impeachment investigators in November.

“We spent a lot of time … trying to refute this one in the first year of the administration,” Hill said.

Still, Trump keeps the notion alive.

He insisted to Fox News viewers in November that he only withheld aid from Ukraine to investigate corruption in the country, hinting once again that the DNC’s servers are hidden there.