Who has an unlimited checking account with the US Treasurer that enables them to write all the checks they want without regard to having funds in the bank?

The concept of an unlimited checking account, where someone can write checks without having sufficient funds, doesn't exist as a regular banking feature. However, I believe you might be referring to a different scenario.

If a person has the authority to spend money on behalf of the United States government, such as a government official or an agency, they may have access to a treasury account known as the "US Treasurer's Account Symbol (TAS)" or a similar type of account.

These accounts are established by the Department of the Treasury for authorized individuals or entities that handle government transactions. They do not grant unlimited spending power but rather provide a mechanism to manage government funds efficiently.

To get further details on who has access to such accounts, you can research specific instances where individuals or agencies may have been granted such privileges. However, it is important to note that even with these accounts, there are usually limitations and controls to ensure responsible financial management and adherence to appropriate regulations.