This is a real problem. From Steve Benen, on the Maddow Show blog:
...what struck me as especially notable about the new survey results is the persistence of the so-called “reality gap.”
* Unemployment: Under President Obama, job growth has been quite strong, and the unemployment rate has improved dramatically. PPP, however, found that 67% of Trump voters believe the unemployment rate went up under Obama – which is the exact opposite of reality...
* Popular Vote: As of this morning, Hillary Clinton received roughly 2.7 million more votes than Donald Trump, but PPP nevertheless found that 40% of Trump voters believe he won the popular vote – which is, once again, the exact opposite of reality.
* Voter Fraud: Even Trump’s lawyers concede there was no voter fraud in the presidential election, but PPP found that 60% of Trump voters apparently believe “millions” of illegal ballots were cast for Clinton in 2016 – which isn’t even close to resembling reality.
As Benen notes, when a sizable percentage of our country is invested in believing -- for whatever reason -- what is transparently a lie, it's hard to know how we're going to move forward.