Also, registration as a professional is generally covered under State law. In my State, performing actions deemed to belong to the medical profession while not registered will run you afoul of State statute.
I was specifically referring to misrepresentations of past performance on the part of politicians to specifically embellish their record in order to be elected. Yes, it is a lie; no it is not prosecuted. Unless, of course, you embellished your record by stating you received military honors. That type of lie was very prominent after WWII, a la Joe McCarthy. It was never prosecuted, or even illegal.
Promise of future performance would be different, otherwise a lot of lounge lizards could be thrown in jail, either directly from the bar room or from the computer seat while on a dating site. As wedding vows are recogized social contract and contract, how many adulterers get 1 year in prison or a fine?
The decision reads, to me, the same as many prior cases built on the Contracts clause, which predates the Constitution. Taken under that clause, it could be prosecuted.