I don't mean to be argumentative, but this statement is untrue.
The Leahy letter was discovered unopened. According to The New York Times, the Leahy letter contained 0.871 grams of refined powder or approximately 871,000,000,000 spores. That's more than what you need to create a "couple of cultures."
The New York Post letter was also recovered unopened, although it had somehow gotten damp, so the unrefined powder was clumped and looked like "Puppy Chow."
And while the Leahy letter had been opened, it was evidently set aside as soon as the envelope was cut open and a puff of powder escaped. Most of the contents should have been intact.
While about 1.5 grams of refined powder and less than a gram of unrefined powder is not a lot for the kazillion tests they wanted to perform, it was more than enough to make SOLID SCIENTIFIC EVALUATIONS of the nature of the powder in the letters. The ONLY guesswork involved here is the guesswork used by the conspiracy theorists to promote their theories.
Ed,
I think you would agree, though, that they definitely sought to prioritize their experiments given the small product available for testing. You better than me, could lay your hands on the quote by the keeper of the product, that it pained him to give up a little more, as there was so little left.