Members of Congress are threatening to oppose the proposed sale of precision-guided missiles to Saudi Arabia unless the Bush administration can guarantee that those weapons will not be turned on the United States or Israel in the future.

Rep. Mark Kirk (R-Ill.) and Rep. Christopher Carney (D-Pa.) are circulating a letter on the Hill expressing their concern about the possible sale of Joint Directed Attack Munitions (JDAM) made by Boeing [BA] to the Middle Eastern country.

“JDAM technology transforms unguided conventional bombs into precision munitions with highly accurate targeting capabilities. If it falls into the wrong hands, JDAM technology could significantly harm U.S. forces in the region and undercut Israel’s qualitative military edge,” they said in the letter.

In July, the State Department announced the potential for a strategic assistance package worth $20 billion in arms sales to Saudi Arabia (Defense Daily, July 31).

At the time number of other lawmakers, led by Rep. Jerold Nadler and Rep. Anthony Weiner– both New York Democrats–announced their intent to block the deal primarily because it could contain JDAMs.

Kirk said he has discussed the arms deal with members of the administration and said some want further assurances that JDAMs sold to the Saudis would not pose a threat to the United States or to Israel. This letter would add strength to that effort at the right time.

“I think the package is not in concrete right now; it’s in wet oatmeal,” Kirk said.

But Nadler and Weiner questioned the premise of that position, asking how such assurances could be guaranteed.

“All foreign military sales have conditions,” Nadler said. “But how do you enforce them?”

The sale of JDAMs to Saudi Arabia would change the balance of power between the two nations, he said adding that the U.S. should not fuel a Middle East arms race.

Even though Congress must sign off on arms sales, it would be difficult to block, Nadler said, because it would require a two-thirds margin in both the House and Senate to override a presidential veto.

Typically there is an attempt to resolve differences within arms sales before a vote is taken, Weiner said.