Judging by the publicity accorded it, it's safe to conclude that the Israeli government believes that the joint Juniper Cobra air defense drill with the United States enhances the country's national security. This may be a premature judgment.
To begin with, the exercise and hype show everyone that Israel is, at the least, unsure of its ability to defend effectively against missile strikes by Iran and possibly others without the help of its ally the United States. This would not be the first time this lack has been exposed; during the two Gulf wars, similar scenarios unfolded.
But airing anew this vulnerability also undermines any offensive option Israel might have hinted at to pressure Iran to stop its program. It suggests that Israel will think twice before going after Iran's nuclear facilities given that its own defenses against retaliatory missile attacks are insufficient. Moreover, filling the defensive gap with U.S. capabilities would all but nullify a military undertaking, considering Washington is on record as firmly opposing an Israeli preemptive attack.

