Can you please make the argument that licensing in general is a poll tax? This statement seems very outlandish to me and I cannot find any papers or articles to support it.

The equal protection argument also seems incorrect to me. If this were the case, states would be under scrutiny for basically any discrepancy between their laws. Why should voters in Texas be required to show IDs when those in California aren't? Why should drivers in Wisconsin keep getting their license back after their 5th DUI when people in another state lose it after 2?