They’re really one and the same class.
The criminals insisted on the distinction...
In general criminality is a stupidity disorder. So to say a smarter criminal is oxymoronic. However! There is a certain innocence presumed upon the stupid by the public that can be very helpful politically. So you will have stupid criminals who become successful politicians when that stupidity appears as a childish innocence.
Still, most politicians are neither stupid nor criminal. They are exploitive of opportunity, however.
And because of the criminal indemnity accorded politicians both in law and in custom, that exploitation of the public weal to serve their selfish interests often crosses over to what would be criminal if done by someone in the private sector.
But as long as the voting public elects politicians who are popular and can talk up a good story, and the character issue -- good moral character is the main check against bad behavior in political office -- is an unimportant metric to voters, we'll have a constant class of quasi-criminal politicians.