The House is expected to vote this week on a bill that calls on the Pentagon to start on an East Coast Ground-based Midcourse Defense (GMD) system site. The bill also lays out beginning parameters for how to choose the location.

But before any of that becomes law, it will have to be hashed out in the Senate, where the leaders of the subcommittee in charge of missile systems are far from mutually assured.

The House is expected to vote on its version of the bill May 18. And the Senate Armed Services Committee is scheduled to draft its version next week.

Sen. Jeff Sessions (Ala.), the top Republican on the Senate Armed Services strategic forces subcommittee, says the East Coast GMD site is one he proposed last year. GMD interceptors are currently based at Fort Greely, Alaska and Vandenberg AFB, Calif.

“We’ve invested billions of dollars. We’ve proven this technology,” says Sessions, who represents the state where much of the GMD development work was conducted. “An extra site would clearly provide extra protection. And I think it would validate our investment. It’s such an unacceptable thing to have developed a system that will work and then not deploy it.”

But Sen. Ben Nelson (D-Neb.), who chairs the subcommittee, dismisses the idea as election-year politics. “One of the considerations for the location of the missile defense system in the European-Asian area is that it will protect not only the United States but a large part of Europe and Asia from the Iranian threat,” he says. “To me, to talk about spending more money to put a system on our east coastline just hasn’t been vetted. It’s just a last-minute idea dropped into a bill.”

Nelson allowed that he could support a study of whether to undertake such a site, if that resulted from a conference discussion resolving differences between the House and Senate versions of the defense policy bill.

“But I’d want to know what the threat is that would not be prevented in Europe and what the costs would be, is this in lieu of or in addition to [other missile defense systems], and where do they propose to get the money,” Nelson says.