Chicago aldermen gather Thursday to question city officials about marijuana. Mayor Rahm Emanuel wants to let cops write tickets when they catch people holding 15 grams or less of the drug.

Aldermen have lots of questions about the pot proposal that’ll likely come up today at a committee hearing:

How will an officer weigh the drug, or even prove that the suspected marijuana is actually marijuana? Will the officer have to drive back to the station after each ticket to lock up the evidence? Will offenders be less likely to share information with police when they know they’re just facing a ticket instead of an arrest?

“Until we are all satisfied that the majority of the issues are out on the table, they’ve been discussed and that we know what the answers are, and they’re reasonable, at that point we go out and try to get people to come along and agree with us,” 40th Ward Ald. Pat O’Connor, Emanuel’s floor leader, said Wednesday.

Twenty-seven of the 50 aldermen signed on to an earlier version of the marijuana ticket plan. O’Connor was not one of them.

Still, he’s predicting passage, but said it could be Emanuel’s closest vote in the city council yet.