Israel has conducted an aggressive campaign of economic espionage in the United States since 1948. This campaign has been critical to sustaining and modernizing Israel's nuclear weapons program and an array of its most advanced conventional weapons even while it has caused American firms to lose valuable proprietary information and unfairly advantaged Israeli companies in the international arms market. While other countries conduct economic espionage against the United States, Israel is the only major recipient of U.S. foreign aid to do so.