There appears to be no shortage of enthusiasm on Capitol Hill for the establishment of a third missile interceptor site in the United States. 

The House Armed Services Committee, in marking up defense spending legislation last week, authorized their colleagues on the Appropriations Committee to provide $140 million next year for the effort, which is a lot of money considering that the U.S. Missile Defense Agency (MDA) has yet to choose a suitable site location, much less lay the groundwork necessary for construction to begin.

Speaking of location, lawmakers have been generous with their thoughts on where it should be. Members of the North Dakota delegation, for example, wrote U.S. Defense Secretary Chuck Hagel in May touting their home state, naturally, as an ideal location, never mind the prevailing sense that the eastern portion of the country is most vulnerable to missile threats. Meanwhile, Sen. Charles Schumer, a New York Democrat not known for missile defense advocacy, wrote Mr. Hagel to offer up New York, which at least is on the eastern seaboard and was mentioned as a possibility in a National Research Council study on missile defense.

U.S. Navy Vice Adm. James Syring, director of the MDA, told lawmakers during a May 8 hearing that it would take 18 to 24 months to conduct an environmental assessment of whichever site the agency deems most suitable. That wasn’t good enough for Rep. Doug Lamborn (R-Colo.), who indicated that some sort of waiver might be needed to expedite the process.

All this kibitzing isn’t terribly helpful. The most compelling rationale for the so-called third site is protection of East Coast cities, which might someday be vulnerable to a missile strike from the Middle East. The North Korean threat is already addressed by interceptors based in California and Alaska, and Mr. Hagel in March announced plans to expand defenses in Alaska. Moreover, while the National Research Council report said an East Coast site would enhance protection against certain threats, it emphasized that to be truly effective, the site would need to be equipped with high-speed interceptors that currently do not exist.

Congressional advocates of a third missile defense site clearly are anxious to get moving, but no amount of money is going to make this happen overnight. Lawmakers need to take a step back and let the MDA figure where to locate — and how to equip — installations to address the missile threat as it continues to evolve. Forcing the issue will more likely than not result in the expenditure of scarce resources on the wrong solutions.