Congress and the Barack Obama administration are once again on a collision course over missile defense aid for Israel as lawmakers begin to mark up their Defense bills for the next fiscal year. 

The House Armed Services Committee on April 27 took up an annual Defense bill that would authorize $332 million for Iron Dome and other defensive systems, more than double the $145.8 million included in the Department of Defense request. Meanwhile, the purse-string holders in the Senate have made it clear that they will seek a substantial increase over the Pentagon's request, which is on top of the $1.3 billion in annual military assistance to Israel under a 10-year Memorandum of Understanding (MOU) that expires in 2018. 

"For the past three years, we've been spending about $600 million to help their missile defense program," Senate Defense Appropriations panel member Lindsey Graham, R-S.C., told Al-Monitor. "I want to lock that in if we can."

Last month, 30 members of both parties signed on to a letter to Defense appropriations leaders Thad Cochran, R-Miss., and Dick Durbin, D-Ill., urging them to meet and exceed Obama's budget request. The letter was spearheaded by Sens. Mark Kirk, R-Ill., and Kirsten Gillibrand, D-N.Y.