Israel's major aerospace company hired former U.S. Attorney General John Ashcroft's lobbying firm late last month to help secure the U.S. government's approval to sell a weapons system to the South Korean Air Force, according to lobbying disclosure records.

The South Koreans are choosing between an early-warning radar system built by Israel Aircraft Industries (IAI) and a similar, more expensive system built by Chicago-based Boeing Co. The radar systems enhance an air force's ability to track enemy fighter jets during combat.

U.S. law requires Israel, and any other country seeking to resell American military technology, to secure approval from the Department of State's Directorate of Defense Trade Controls. That agency can also consult with the Pentagon on whether to issue an export license. A State Department spokesman declined to comment.

Boeing already has the U.S. government's approval.

The South Koreans initially had intended to make a decision by Dec. 31, but the government told the companies last month that it would delay its final decision until May 2006, which gives the Israeli company an additional four months to get the U.S. government's blessing.

Boeing officials based in Seoul, South Korea, expressed disappointment with the four-month delay in news reports in that country and Israel. The Jerusalem Post reported last month that Alexander Vershbow, the U.S. ambassador to South Korea, met with the South Korean defense minister and pushed for Boeing. The $1 billion deal has garnered little attention in the U.S. media and in Congress.

In 2005, Boeing contributed $642,877 to Republican and Democratic lawmakers' political action committees and campaign committees, according to politicalmoneyline.com. The firm reported spending $4.9 million on lobbying in 2004.

A spokesman for Rep. Norm Dicks (D-Wash.), who traditionally aids Boeing because the company has a large presence in his district, said he was not aware of the sale and had not been contacted by Boeing on the matter. Spokespeople for Speaker Dennis Hastert (R-Ill.), Rep. Mark Kirk (R-Ill.) and Washington Democratic Sens. Patty Murray and Maria Cantwell did not return calls for comment.

South Korea, the world's 11th largest economy, has been investing heavily in its military in recent years. The U.S. ally has developed its own fighter plane and battle tank and launched an aircraft carrier, destroyers and submarines, said John Pike of GlobalSecurity.org, an intelligence research company.

"The [surveillance] technology makes a tremendous difference whether you have airplanes like this," Pike said, adding that not having the system is like having a "football team without a coach and captain. It is night-and-day in terms of efficiency and effectiveness of air power. Any serious, self-respecting country wants them or wants to get them."

The Ashcroft Group and IAI signed a nondisclosure agreement, said spokeswoman Juleanna Glover Weiss, and IAI officials based in D.C. and Tel Aviv said the company does not comment on its consultants. Ashcroft has built a lucrative lobbying practice since starting last summer. Public records also show that Oracle; ChoicePoint, a company that sells data to police and federal law-enforcement agencies; and the American Institute of Certified Public Accountants have hired Ashcroft.

Public records do not disclose how much IAI is paying Ashcroft. The records show that IAI also hired Morris Amitay for $20,000. "I am not going to comment," Amitay said, referring to questions about the potential deal to IAI's office in Arlington, Va.

While it is not unusual for foreign governments to hire Washington lobbyists to navigate the executive-branch bureaucracy, Congress has a record of inserting itself into commercial transactions, especially when national-security issues are concerned. For example, the House overwhelmingly passed two resolutions last year encouraging the Bush administration to stop a potential merger between a Chinese oil company and Unocal, a U.S. oil company.

Israel has come under criticism from the U.S. government for selling arms to countries hostile to the United States, such as China and South Africa. In 2000, pressure from the Clinton administration and Congress stopped Israel from selling its Phalcon radar system to the Chinese.

"Past Israeli behavior does not inspire confidence," said Loren Thompson of the Lexington Institute, adding that past actions could spark Congressional action.

The United States suspended cooperation with Israel last year on some long-term military projects after Israel announced plans to sell China spare parts for Harpy Drone unmanned aerial vehicles. The United States and Israel signed a memorandum of understanding in August to regulate future arms sales between Israel and other countries.

Boeing has sold its surveillance system to the Australian and Turkish governments, said a D.C.-based Boeing official, who declined further comment. Last year, the Israelis sold the Phalcon system to India's air force, and, previously, they sold the Phalcon system to the Chilean air force.

The United States approved $22.4 billion in licenses to sell arms in 2004; Israel accounted for $1.33 billion in sales. Japan and Great Britain were the largest buyers of U.S. weapons, according to a State Department report.

Jonathan E. Kaplan is a staff reporter for The Hill.