As a result, Massachusetts was the only northern state in any way prepared for war when the Confederates fired on Fort Sumter; and her troops began to muster in Boston on the 16th of April, the very day after President Lincoln's call for volunteers.
While a pair of dark cotton pants may pass muster in dressy environments as a last resort, the same can't be said for, say, a polo shirt or a T-shirt.
Though it's not appropriate for, say, a fancy dress party, it certainly passes muster in other circumstances.