Moving a Roth from one broker to another. The value of the original account has decreased below the original total of contributions, is the basis still considered the total contributions?
Your basis in a Roth IRA is the amount of your own contributions to it. Your Roth IRA is the aggregate of all Roth accounts that you might have and the basis applies to the Roth as a whole. If the value of the aggregate IRA is below your basis and you sell, unfortunately you can no longer claim the loss due to tax law changes.
Moving accounts from one trustee to another has no effect.