It's completely 100% moot.
School vouchers is the perfect wedge issue, or should be, but does anyone seriously think it'll even affect 1% of the inner city minority vote?
These are people who send the likes of Cynthia Mickenny and Carolyn Mosley Braun to Washington, and in Washington itself, re-elect Marion Barry as their mayor. And cheer on "civil rights leaders" the stripe of Jesse Jackson and Al Sharpton, when it is blatantly obvious they only exist to enrich themselves.
This constituency does not do so because they are fooled, they do it on purpose. The inner city minority electorate as a whole would rather knowingly elect and support these people because they believe (correctly) that it irritates the rest of America, and do so at the expense of real agendas that would help them.