It used to be hard, but now anyone can find out if anyone is a criminal. At least in the USA.
Criminal Searches has made it easy. This stuff has been online for a while, but CS is the first ad supported, free to search model.
I checked, and it seems that I am clean.
But one George W Bush apparently was convicted of Fraud in Texas in 1987, and Hillary Clinton was done for Marijuana selling in 1994.
Actually that Hillary was a bloke.
Which says it all – be careful what you read when it comes to this stuff, and do check yourself – and follow up with the relevant authority if it is wrong.