President Trump has approved a memorandum that would enforce the obligations of sponsors to reimburse the government when immigrants receive means-tested public benefits.
As part of the permanent residence process for family-based immigrants, a US resident signs an I-864 Affidavit of Support. The sponsor accepts legal responsibility for financially supporting this foreign national. This legally enforceable responsibility lasts until the foreign national becomes a U.S. citizen or can be credited with 40 quarters of work (usually 10 years), even if the relationship (e.g. marriage) ends before that time.
In most cases, the Affidavit is completed only by the US family member that is petitioning for the foreign national (e.g. a US citizen woman bringing her foreign spouse to the US). In some cases, the petitioner's income is not enough for her to act as sponsor, however, so a joint sponsor is needed. Fore more information about Affidavits of Support, see here.
The Affidavit of Support has been required since 1997, pursuant to the Illegal Immigration Reform and Immigrant Responsibility Act of 1996. Section 213A of the Immigration and Nationality Act requires that any government or non-government entity that provides a means-tested public benefit to a sponsored alien shall request reimbursement from the sponsor in an amount equal to the unreimbursed cost of such benefit.
In reality, this reimbursement provision has rarely been enforced, although it is a significant responsibility that sponsors should be very aware of. In my practice, I have always insisted on counselling the sponsor about the importance of the Affidavit and the obligations under it, even though I have never seen it enforced.
White House statement.
Elaine Martin has been practising US and global immigration law since 1997. She is an immigrant herself (from Ireland), so has a special understanding of the legal and emotional challenges involved in relocating to a new country.