President Donald Trump advanced a dizzying number of wrong or misleading claims in 2019, but none so central to his legacy — and the news cycle — as the torrent of falsehoods about the dealings with Ukraine that led to his impeachment.

Since he exploded onto the national political stage more than four years ago with the false claim that Mexico was funneling criminals into the United States, the president has frequently used falsehoods to attack his rivals and overstate his popularity and successes. We fact-checked his claims, sometimes repeatedly, as they've guided U.S. policy on everything from trade to immigration.

This year, the president promoted conspiracy theories about Ukraine and inaccurate claims about how tariffs work in an attempt to spin his trade war with China as a win — even as the data showed that Americans, including farmers, were paying the price. Other, smaller falsehoods still made headlines.

Here are 10 baseless, misleading or confounding claims Trump made this year, and the facts — plus one oft-repeated claim that finally, in late October, became true.

Claim 1: Ukraine interfered in the 2016 election

This claim is false, according to the unanimous assessment of the U.S. intelligence community and the former special counsel Robert Mueller, who spent two years investigating Russia's election interference effort.

The Russian government, not Ukraine, interfered in the 2016 election "in sweeping and systematic fashion," the Mueller report concluded, working to boost Trump's bid while damaging his Democratic rival, Hillary Rodham Clinton.

Still, in both private and public remarks, as well as in the pivotal July 25 phone call with Ukraine's new president, Trump repeatedly pushed or referenced a conspiracy theory that Ukraine and the Democrats framed Russia for election meddling in an attempt to discredit his presidency.

In that now-famous July phone call with Ukrainian President Volodymyr Zelenskiy, the same call in which Trump asked for investigations into former Vice President Joe Biden and his son Hunter, Trump danced around the theory. He talked about “this whole situation with Ukraine," Democratic computer servers, and “CrowdStrike," the private cybersecurity firm initially hired by the Democratic National Committee to investigate a breach that the FBI ultimately concluded was a hack and dump scheme engineered by Moscow as part of a larger, pro-Trump influence campaign.

"The server, they say Ukraine has it," Trump said, according to a White House record of the call.

“I would like you to get to the bottom of it," he continued later. "They say a lot of it started with Ukraine.”

Later, he would suggest to reporters that Clinton's emails might be in Ukraine.

In fact, there is no evidence that Ukraine mounted any sort of election interference effort. Ukraine isn't harboring a Democratic server, and Clinton’s emails are not hiding there, either. Members of Trump's own administration, including former Department of Homeland Security Secretary Tom Bossert, have said they tried to tell Trump this wasn't true.

The conspiracy, which was first publicly posted on a far-right message board, 4chan, in March 2017, appears to be part of Trump's broader, yearslong effort to discredit Mueller's investigation and undercut the idea that a foreign government helped get him elected.

In late 2019, Trump's unfounded fascination with Ukraine became inextricably tied to separate false claims about Biden, who is running to challenge him in the 2020 election, and featured heavily in the House's impeachment inquiry into whether Trump abused the power of his office by attempting to pressure a vulnerable ally into announcing investigations into the Bidens and Democrats that could boost his bid for re-election.

During weeks of hearings over the course of the House's impeachment inquiry, members of the State Department, Defense Department and Trump's own administration testified again and again that Russia — not Ukraine, and not the former vice president — were the bad actors.

Trump's former Russia expert, Fiona Hill, called the idea that Ukraine meddled in 2016 a "fictional narrative" promoted by Russian intelligence and rebuked House Republicans for using it to defend the president against impeachment. Trump, and members of the GOP, have contended that the actions his administration took toward Ukraine were motivated not by political or personal interest, but by legitimate concern about corruption in the country, including alleged Ukrainian election interference.

"In the course of this investigation, I would ask that you please not promote politically driven falsehoods that so clearly advance Russian interests," Hill said in her opening statement to Congress. "I refuse to be part of an effort to legitimize an alternate narrative that the Ukrainian government is a U.S. adversary, and that Ukraine — not Russia —attacked us in 2016."

Claim 2: Biden acted corruptly as vice president to benefit his son

Trump has said he discussed political rival Biden with the president of Ukraine — a phone call at the heart of the intelligence community whistleblower's complaint that led to the launch of the formal impeachment proceedings in the House — for one reason: a desire to root out corruption.

The former vice president, Trump said, wielded his influence to benefit his son Hunter’s private-sector work in Ukraine. In May, Trump said that Biden improperly got a Ukrainian prosecutor fired, a claim he went on to repeat in the July phone call with Zelenskiy. Trump would later add this ousting was to protect Hunter Biden, who served on the board of a Ukrainian energy company at the time.

But despite Trump's continued claims, there's no evidence of wrongdoing on the part of either Biden. Removing that prosecutor was U.S. policy under the administration of President Barack Obama. While Obama administration officials raised concerns at the time about the appearance of a conflict of interest that Hunter Biden's work posed for the vice president, U.S. officials testified as part of the impeachment inquiry into Trump that there was no evidence Biden himself worked toward anything other than enacting U.S. policy.

Claim 3: The whistleblower made a "false account"

In September, news broke that an anonymous person within the intelligence community had filed a formal whistleblower complaint related to the president's dealings with Ukraine, including that July phone call with Zelenskiy, and that the Trump administration was withholding that complaint from Congress.

By the end of the month, Congress had obtained the whistleblower's nine-page complaint, which the author wrote was lodged out of the belief that Trump was "using the power of his office to solicit interference from a foreign country" in the 2020 election and detailed alleged actions by the president and other government officials to pressure Ukraine into opening politically advantageous investigations.

The House Intelligence Committee, on Sept. 26, released a declassified version of the complaint to the public as part of the formal investigation into the whistleblower's allegations. Subsequently, Trump made several inaccurate claims about that complaint, charging that the still-unnamed whistleblower had made a "false account."

“He got his information, I guess, second or third hand. He wrote something that was total fiction," Trump said in October.

"The whistleblower gave a false account," Trump said on another day in October.

"Sooo wrong," he wrote in a tweet in November.

There's no evidence to support this — rather, the available evidence supports the whistleblower. The actions and conversations described in the whistleblower complaint have been largely corroborated, both by the record of the Zelenskiy call that the White House released, as well as sworn testimony of Trump aides, an exhaustive NPR report shows.

The Ukraine whistleblower used both firsthand and secondhand information in the complaint, according to the Office of the Inspector General of the Intelligence Community. Michael Horowitz, the inspector general, noted this is an acceptable practice in a whistleblower complaint.

Claim 4: Article II of the Constitution lets me “do whatever I want”

"Article II allows me to do whatever I want,” Trump told ABC News in June.

"Then I have an Article II, where I have the right to do whatever I want as president,” he said in Washington in July.

Article II of the Constitution establishes the executive branch and outlines the presidency’s power. It does grant the president a lot of power, but it does not say he can do whatever he wants, unfettered. What's more, Article II of the Constitution also outlines impeachment as a recourse for a problematic president: “The President, Vice President and all Civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.”

Article I of the Constitution deputizes lawmakers in the process: the House is given the powers of impeachment, while the Senate is tasked with trying and deciding whether to remove an individual who has been impeached.

Claim 5: We're "taxing the hell out of China" with tariffs

“You’re not paying for those tariffs. China’s paying for those tariffs,” the president told an Ohio crowd in August. “Until such time as there is a deal, we will be taxing the hell out of China.”

Trump continued to use a fundamental misunderstanding of tariffs to defend U.S. trade policy this year, repeatedly telling voters that the country was using tariffs to cash in on the wealth of other countries.

Economists and experts told NBC News that this is false. Consumers purchasing foreign goods are the ones who picked up the tab. In August, J.P. Morgan estimated the cost of these tariffs on average U.S. families was more than $1,000.

Claim 6: The Mueller report "totally exonerated" Trump

“Complete and total exoneration,” Trump wrote in one tweet in March after the Mueller report was released. It's an inaccurate claim he repeated often.

House Judiciary Committee Chairman Jerry Nadler, D-N.Y., asked the former special counsel about this claim during a congressional hearing: “Did you actually totally exonerate the president?”

“No,” Mueller said.

Mueller's written report was clear on this, too: "If we had confidence after a thorough investigation of the facts that the President clearly did not commit obstruction of justice, we would so state," the report reads in part. "While this report does not conclude that the President committed a crime, it also does not exonerate him."

Claim 7: Where Hurricane Dorian was expected to hit

In September, the president came under fire for tweeting that Hurricane Dorian was expected to hit Alabama despite the fact that the vast majority of forecasts said it would not, according to a review by The Associated Press.

The National Weather Service in Birmingham, Alabama, tweeted to say Dorian would not affect the state. The president continued to insist he was correct, even apparently altering a map with a marker in the Oval Office to reflect this view. While the National Oceanic and Atmospheric Administration would later offer a statement from an unidentified spokesman saying the president was right at the time, onlookers remained doubtful.

Claim 8: Windmills cause cancer

The president has repeatedly advocated against wind energy in a way that has perplexed scientists and fact checkers. In April, he said the noise from windmills cause cancer and are a “graveyard” for birds. “They kill all the birds,” he said in August.

The American Cancer Society has rejected the claim that windmills or the sound of them cause cancer. Wind turbines do kill birds, though cats and cell towers kill significantly more winged creatures.

Claim 9: Toilet flushes are up

"People are flushing toilets 10 times, 15 times, as opposed to once. They end up using more water. So, EPA is looking at that very strongly, at my suggestion," Trump said in December, referring to the Environmental Protection Agency.

Water preservation restrictions have been on the books since the 1990s dictating how much water is used by toilets, but there’s no evidence that low-flow toilets are creating 10-plus flush situations for anyone. While Trump says he's ordered a review, the review was mandated by a 2018 law, Vox reported.

Claim 10: Mars and the moon

"We’ll be going to Mars very soon," Trump said in May during a news conference with the Japanese president.

This timeline is not accurate. There won't be Americans — or anyone else — on Mars for at least a decade, according to The Associated Press, which adds that international space agencies aspire to reach Mars in the 2030s.

The next month, Trump tweeted more about U.S. ambitions in space.

NASA “should be focused on the much bigger things we are doing, including Mars (of which the Moon is a part), Defense and Science!” Trump tweeted in June.

This confusingly-worded tweet suggests that the moon is part of Mars — it is definitely not. Trump could have been referring to NASA's "Moon to Mars" program that would establish a human presence on the moon as part of its larger effort to get to Mars and beyond, but it's worth noting that the moon is a satellite of Earth.

Bonus: The wall is being built

"The wall still, obviously, has a ways to go, but we’re building it at a breakneck speed," Trump said in September.

Trump has been taking credit for building a new border wall for years now. It was 2018's top falsehood, and the claim was false for most of this year, too. But in late October, The New York Times reports, the Trump administration finally broke ground on a new stretch in Texas. Previously, the construction Trump boasted about amounted to the replacement of old sections — not a new border barrier.

It's not the concrete wall Trump campaigned on, Mexico is still not paying for it, nor is the wall being built in Colorado, as Trump claimed in October, since the Centennial State does not border Mexico. But it is, at long last, a new stretch of border barrier for which he can claim credit.