Uh...
https://en.wikipedia.org/wiki/Bill_Clinton_sexual_misconduct_allegationshttps://en.wikipedia.org/wiki/Troopergate_(Bill_Clinton)Among many others that could be listed.
And in Clinton's case, he wouldn't call them a liar, because wife Hillary did that for him, leading the charge to slander and destroy Clinton's accusers, women
Hillary knew to be telling the truth. But destroyed them anyway, just to advance her own political ambitions.
And again, while there are allegations against Trump, they are not proven. The allegations against Bill Clinton and Al Franken
are proven.