Also, if your letter is inside of an envelope it will be left unopened in a warehouse for several weeks or months in an attempt to kill anything biologically active inside of it.
It will then be opened in a separate processing facility away from the White House in the event of chemical attack or contamination.
Result: You are not "heard" by anyone, even a low level $10 an hour mail sorter/reader in a security checkpoint, for a couple of months after legislation has already passed.
If you want to actually be heard, make it shorter and put it on a postcard. A postcard has no container, so can't carry any threatening agents on it. It will be read upon receipt and your voice (such as it is) will have a faster effect and response (if any at all).