While I commend your efforts, the letter is too long and pointless. Congressmen do not read letters sent to them. They do receive breifings on the general drift of support or opposition to issues.
A short letter will be just as effective.
Plus, the issue will not be decided, or voted on, based on logic or the Constitution. The votes will be decided by political pressure, emotion and the beliefs of the Members voting. Meaning only heavy lobbying will have any effect.