42 USC 407 - Assignment of benefits

(a) In general 
The right of any person to any future payment under this subchapter shall not be transferable or assignable, at law or in equity, and none of the moneys paid or payable or rights existing under this subchapter shall be subject to execution, levy, attachment, garnishment, or other legal process, or to the operation of any bankruptcy or insolvency law.
(b) Amendment of section 
No other provision of law, enacted before, on, or after April 20, 1983, may be construed to limit, supersede, or otherwise modify the provisions of this section except to the extent that it does so by express reference to this section.
(c) Withholding of taxes 
Nothing in this section shall be construed to prohibit withholding taxes from any benefit under this subchapter, if such withholding is done pursuant to a request made in accordance with section 3402(p)(1) of the Internal Revenue Code of 1986 by the person entitled to such benefit or such persons representative payee.