I am writing this post because I recently got this question.
Under Illinois’s concealed carry law 430 ILCS 66/70(d) :
A licensee shall not carry a concealed firearm while under the influence of alcohol,
other drug or drugs, intoxicating compound or combination of compounds, or any
combination thereof, under the standards set forth in subsection (a) of
Section 11-501 of the Illinois Vehicle Code.
A licensee in violation of this subsection (d) shall be guilty of a Class
A misdemeanor for a first or second violation and a Class 4 felony for a
third violation. The Department may suspend a license for up to 6
months for a second violation and shall permanently revoke a license for
a third violation.
Pretty straightforward, isn’t it?