Is it legal to drive in Illinois when the passenger is drunk? More details below.?

Not sure about Illinois, but here in Georgia, it would be. According to Georgia code...

40-5-24.

(a)(1) Any resident of this state who is at least 15 years of age may apply to the department for an instruction permit to operate a noncommercial Class C vehicle. The department shall, after the applicant has successfully passed all parts of the examination referred to in Code Section 40-5-27 other than the driving test, issue to the applicant an instruction permit which shall entitle the applicant, while having such permit in his or her immediate possession, to drive a Class C vehicle upon the public highways for a period of two years when accompanied by a person at least 21 years of age who is licensed as a driver for a commercial or noncommercial Class C vehicle, who is fit and capable of exercising control over the vehicle, and who is occupying a seat beside the driver.

Notice the "who is fit and capable" part. Now I read Illinois code, which states

(625 ILCS 5/6‑107.1)

1) An instruction permit issued under this Section

shall be valid for a period of 24 months after the date of its issuance and shall be restricted, by the Secretary of State, to the operation of a motor vehicle by the minor only when accompanied by the adult instructor of a driver education program during enrollment in the program or when practicing with a parent, legal guardian, family member, or a person in loco parentis who is 21 years of age or more, has a license classification to operate such vehicle and at least one year of driving experience, and who is occupying a seat beside the driver.

Note that there is nothing about the other occupant being "fit to operate" the vehicle. One would assume that the purpose of the Instructional Permit would be to provide for an "Instructor". I don't feel that an intoxicated person would be fit to be so, but the legislature apparantly did not address that issue, unless they did so elswehere in Illinois code. It COULD come down to being at the descretion of whatever judge heard the case. My suggestion is to play it safe and have someone else drive. You wouldn't want to be the cause of the case law that prompted the legislature to amend the code to insert that little phrase.

The official website does not say anything about the passenger being sober...

Permit Phase Drivers Age 15

Parental or guardian consent required to obtain an instruction permit.

Curfew is Sunday through Thursday, 11 p.m.; Friday and Saturday, 12:01 a.m. (local curfews may differ)

Must be enrolled in an approved driver education course and must pass vision and knowledge tests

All occupants under age 19 must wear safety belts

Number of passengers limited to one in the front seat and the number of seat belts in the back seat

Practice driving 50 hours, including 10 hours of night driving, supervised by parent or an adult age 21 or order with a valid driver's license

Permit must be held for a minimum of three months

Permit is valid for up to two years.

Sanctions

Limit of one court supervision for serious offenses

Conviction of a serious moving violation results in a six-month waiting period applying for a driver's license

Not eligible for a restricted or judicial driving permit

Anyone caught driving without a permit will be ineligible to obtain a driver's license until age 18

until u pass the driving test to get ur full license, u technically have no license, and not legal to drive. u are actually driving on ur parents' license. if u get pulled over, or u wind up running into a sobriety checkpoint, u could wind up getting a 'no license' ticket, and the stepdad...or other licensed driver, might wind up getting a dwi ticket. only if u have a full license would u be legally able to be the designated driver. dont take a chance.

probably not legal . the reason you need someone in the car with you, is to help if you get into trouble, can't if he is drunk. call a taxi or safe ride

NO. It is not legal. He is in there for a reason, and that is not to be impaired.

No, it is not illegal, as long as he is not passed out (and maybe even then).

That is the whole purpose of the designiated driver program.

no it's not legal, he is there to help you learn and what good is he if he is drunk? .

Use common sense, it is not legal.