Whoever corruptly or by force or threats of force (including any threatening letter or communication) attempts to intimidate or impede any officer, employee, or contractor of the Social Security Administration (including any State employee of a disability determination service or any other individual designated by the Commissioner of Social Security) acting in an official capacity to carry out a duty under this chapter, or in any other way corruptly or by force or threats of force (including any threatening letter or communication) obstructs or impedes, or attempts to obstruct or impede, the due administration of this chapter, shall be fined not more than $5,000, imprisoned not more than 3 years, or both, except that if the offense is committed only by threats of force, the person shall be fined not more than $3,000, imprisoned not more than 1 year, or both. In this subsection, the term “threats of force” means threats of harm to the officer or employee of the United States or to a contractor of the Social Security Administration, or to a member of the family of such an officer or employee or contractor.