The United States and its partners in the Middle East have two problems with Iran. One stems from Tehran’s penetration of neighboring states; the other, from its nuclear program, which could yield weapons if left unchecked. The two issues are linked strategically and politically: an Iran with nuclear weapons capability would likely be emboldened in its regional adventurism. And Iranian adventurism empowers those in Washington and in the Middle East who favor imposing, rather than negotiating, limits on Iran’s nuclear program.