It's always risky to celebrate good times, especially in an age when there is no way to rule out that along with the usual perils of life, we will suffer another terrorist attack. But this spring, more than 3 1/2 years after Sept. 11, it does seem that since that day America has weathered a rough passage awfully well. That, and with the cherry trees just done blooming in Washington and New York's Central Park full of flowers (and, in the grand old tradition, amateur baseball teams), it feels worth a moment to stand back and observe that for all...