Donald Trump, having propelled his presidential campaign to victory while often disregarding the truth, now is testing the proposition that he can govern the country that way.
In the first five days of his presidency, Trump has put the enormous power of the nation's highest office behind spurious - and easily disproved - claims.
He began with trivial falsehoods about the size of the crowds at his inauguration but has since escalated a more grave claim that undermines the trustworthiness of the nation's electoral system.
In a White House reception for congressional leaders, Trump alleged that as many as five million undocumented immigrants voted in the 2016 election, denying him a popular-vote majority. It was a claim that Trump had made in the aftermath of the election, with no evidence to back it up.
Beliefs are not the same as facts. Trump's attraction to conspiracy theories and his contempt for facts that tarnish his pride may have serious implications for his ability to govern.
At the California State Capitol, Governor Jerry Brown criticised the new President for his refusal to tether himself to the facts. "Above all else, we have to live in the truth," Brown said.
"When the science is clear or when our own eyes tell us that the seats in this chamber are filled or that the sun is shining, we must say so, not construct some alternate universe of non-facts that we find more pleasing."
Veterans of previous White Houses say they can recall no precedent for what Trump and his top aides are doing.
They worry about the implications of this untethering from the truth when big decisions must be made about dealing with terrorism or charting the course of the economy.
"The degree to which they are creating their own reality, the degree to which they simply make up their own scripts, is striking," said Peter Wehner, a Trump critic who was a top strategist in the George W. Bush White House. "It's a huge deal, because in the end you really can't govern, and you can't persuade people, if you do not have a common basis of fact."
The failure by Trump and his team to maintain discipline will do long-term damage, said Matthew Dowd, who was the chief strategist for George W. Bush's 2004 re-election campaign. "I don't think he realises how much he is hurting himself."
Then again, Trump may well believe that this is the style which brought him to the White House, in defiance of every expectation. Americans knew what they were getting when they elected him.