There's a long history of presidential untruths. Here's why Donald Trump is 'in a class by himself'

As president, Ronald Reagan spoke movingly of the shock and horror he felt as part of a military film crew documenting firsthand the atrocities of the Nazi death camps.

The story wasn’t true.

Years later, an adamant, finger-wagging Bill Clinton looked straight into a live TV camera and told the American people he never had sex with White House intern Monica Lewinsky.

He was lying.

Presidents of all stripes and both major political parties have bent, massaged or shaded the truth, elided uncomfortable facts or otherwise misled the public — unwittingly or, sometimes, very purposefully.