Illinois Senator, Dick Durbin used the "A word"  when  warning Visa/MC (and his comments suggest he has both under his microscope.)  An interesting move by the Senator to say the least.  I must say, he knows the dynamic duopoly's soft-spot.

Antitrust lawsuits are to Visa and MasterCard what Kryptonite is to Superman.  (with apologies to the Dynamic Duo) 

Antitrust Lawsuits are to Visa/MC what Kryptonite is to Superman

"I would caution you not to collude with your largest member banks to change your fees and rules in an effort to protect the big banks against competition from smaller card-issuing banks," Durbin wrote. "Such steps would also raise serious antitrust concerns."

May 27 (Bloomberg) -- Visa Inc. and MasterCard Inc., the world’s biggest payment networks, should “stop threatening small banks” into opposing limits on debit-card interchange fees, and may raise antitrust issues if they “collude” with larger banks, U.S. Senator Richard Durbin said.

“If your companies were to coordinate such punitive actions in the same way that you appear to have coordinated your messaging tactics, serious concerns would be raised that you are engaging in an unlawful restraint of trade,” Durbin, the Illinois Democrat and majority whip, said today in a letter to the chief executive officers of San Francisco-based Visa and Purchase, New York-based MasterCard.