When it comes to providing helmets for U.S. soldiers abroad, the Defense Department hasn’t shown itself to be particularly discriminating in its choice of manufacturers.

Last December, after secret tapes revealed the North Dakota Sioux Manufacturing Company charged with producing helmets for soldiers in Iraq and Afghanistan had knowingly delivered some 2.2 million helmets made with substandard weave, the Defense Department wasn’t fazed by the controversy. Rather, 12 days before the pending Justice Department lawsuit was settled (with a $2-million slap on the wrist), the DOD issued another contract to the Sioux Manufacturing Company worth up to $74 million.

Today, VoteVets.org and Citizens for Responsibility and Ethics in Washington launched a campaign for Congressional inquiry into the contract. Two whistleblowers from Sioux Manufacturing publicly released their recorded tapes with Sioux Manufacturing employees this morning (available with transcripts here); Sens. Kerry and Clinton have joined them in their call.

“We and our families deserve a government that will only give contracts to companies with an unblemished record,” says Jon Schultz, VoteVets.org founder who served in Iraq and Kosovo. “The Bush Pentagon has once again let us down.”

Since the Spirit Lake Nation owns the Sioux Manufacturing Company, the company can assert sovereign immunity in any private lawsuits brought by soldiers.