No we don't. That was a BIG issue during the cold war when the USSR had us outnumbered with tanks and artillery in Europe by about five to one. Meanwhile, the Soviets promoted their "no first strike" policy and lambasted us for not joining them. Despite pressure from "peace" groups, we stood our ground, kept the option and therefore minimized the USSR's ability to intimidate us into accepting agreements that were more to their favor. (That's something else that will not be taught in most universities.)
There was a report that immediately after the attack, the Bush administration was inquiring into the kiloton yield of an exploding fully fueled 757. Speculation was that they were preparing a case for the terrorist having used weapons of mass destruction first.