Their campaign follows a three-year fight over a joint operating arrangement in Detroit.
Opponents of the act contend that newspapers in joint operating arrangements often raise their advertising and circulation rates sharply.
That group opposed the joint operating arrangement in Detroit.
Those who support the law also say that without joint operating arrangements, few cities can support two metropolitan newspapers.
The 1970 act requires Justice Department approval for such a joint operating arrangement.
A move to abolish or curtail the right of newspapers to establish joint operating arrangements is under way.
AT&T's results in both efforts have already been lackluster and it recently moved to reorganize the operating arrangement with Unisource.
No joint operating arrangement has ever been turned down, industry analysts say.
Usually, the stronger newspaper will enter a joint operating arrangement only if the weaker paper is perceived as strong enough to offer long-term competition.
But Mr. Hussman has said he does not want to be in a joint operating arrangement with Gannett.