Military relations between Israel and the United States have been consistently close, reflecting shared security interests in the Middle East. A major purchaser and user of U.S. military equipment, Israel is also involved in the joint development of military technology and regularly engages in joint military exercises involving United States and other forces. The relationship has deepened gradually over time, though, as Alan Dowty puts it, it was "not a simple linear process of growing cooperation, but rather a series of tendentious bargaining situations with different strategic and political components in each."