If Congress prohibited advertising by any firm having any fragment of ownership...

[Boojatta]

by people under the age of 18, then would there be any basis for the prohibition to be challenged in court as unconstitutional?

An example of what the prohibition would mean: either companies traded on the stock exchange would have to stop all advertising or, if any shares were owned by people under the age of 18, then those shares would have to be sold or given away. However, if people under the age of 18 couldn't own any part of firms that advertise, they might nevertheless be able to own corporate bonds, since bonds are debt obligations rather than equity.

[pepperbear]

1. sounds to me like you're saying that no one under the age of 18 would be able to own stock in

a company. am I missing something? There doesn't seem to be a constitutional precedent for that. companies have to be allowed to advertise.

[Boojatta]

2. Since when does Congress need to get prior permission from courts to create a law?

Anyway, there are already a variety of restrictions on minors. The one-drop rule used to affect anyone having merely a single remote ancestor of "the wrong" ancestry. Similarly, a small share of ownership by minors could be a basis for imposing tight restrictions on a company.

Edited to add: I know of no case where a one-drop law was ruled unconstitutional on the grounds that the demands imposed by the law were out of proportion to the amount of ancestry. However, perhaps you could cite a case and add to my knowledge. My understanding is that the key change has been to altogether do away with discrimination based on ancestry. Of course, this has involved both nation-wide and state-level efforts. For example, there has been political activism including civil disobedience, federal law enforcement against opposition by state-level officials, appeals in court, etc.