The U.S. Chamber of Commerce could have filed suit against the National Labor Relations Board anywhere.

But the business group chose Charleston as the place to fight the agency's new rule requiring employers to display posters about employees' rights to unionize because that's where it believes it has the best chance to win.

"Our case raises some of the same issues" as two other suits filed earlier this month in Washington, said L. Gray Geddie Jr., of Ogletree, Deakins, Nash, Smoak & Stewart P.C. in Greenville. "But our case is unique in South Carolina because of our right-to-work law here."

According to the federal lawsuit, the chamber is the world's largest federation of businesses and associations, and thousands of its members would be affected by the NLRB's notification rule.

The U.S. Chamber and its co-plaintiff, the S.C. Chamber of Commerce, allege the NLRB notification rule, which was issued Aug. 30, violates federal labor and regulatory laws as well as the First Amendment.

The suit, filed Monday against the agency, its members and its acting general counsel, seeks to block the rule before it becomes effective Nov. 14.

In a statement Tuesday, the NLRB said it has the requisite rulemaking power and said the rule, "which is available at no charge on the NLRB website, is simply intended to inform employees of their rights under the National Labor Relations Act, just as other workplace posters inform employees of their rights under other laws."

But the chambers fear their business members will "incur substantial monetary costs" associated with posting the notice, explaining it to employees and potentially defending themselves against alleged violations. The rule also would result in "self-censorship," as businesses "will be forced to espouse views with which they do not agree, in contravention of the First Amendment's prohibition against compelled speech," the suit reads.

The National Association of Manufacturers filed a similar suit against the same NLRB defendants on Sept. 8. The National Right to Work Legal Defense and Education Fund, the National Federal of Independent Business and two businesses filed their suit Friday.

The chambers' suit is unrelated to the NLRB's pending case against Boeing, which accuses the aircraft manufacturer of building its 787 Dreamliner plant in North Charleston in retaliation for union strikes in Washington state, was not a motivation, Geddie said.

"Everybody's entitled to their own opinions. Boeing really had nothing to do with the filing of the lawsuit," he said.