We've covered this before. John Q. Dough Jr. is not the same as John Q. Dough II. Use the wrong one if you want to look like an ill-educated wannabe politician...or just someone who's never been to school a day in his life.
This is the correct use of the two:
Or...
Both are used to identify that the person is the second in the family to have the name.
Jr is used when the son has the same name as the father.
The second (II) is used when the elder family member is anyone other than the father.
The Shoals is drowning in politicians with IQs less than 100. Let's not elect anymore...please!