Here from the Illinois Legal Malpractice Blog discussing an ABA Journal article about a 2d Circuit Case.  Immigration legal malpractice is a frequent subject, with inherent problems for the plaintiff.  First, the client may not be in the country, and discovery/depositions will be difficult; second, proving the value of damages can be difficult.  The mistake and the consequences are clear:

"With disturbing frequency, this Court encounters evidence of ineffective representation by attorneys retained by immigrants seeking legal status in this country. We have previously indicated that ineffective assistance of counsel can constitute an "exceptional circumstance" warranting the reopening of a deportation order entered in absentia. See Twum v. INS, 411 F.3d 54, 59 n.4 (2d Cir. 2005). We write today to establish [*2] what we would have thought self-evident: A lawyer who misadvises his client concerning the date of an immigration hearing and then fails to inform the client of the deportation order entered in absentia (or the ramifications thereof) has provided ineffective assistance. We further clarify that such misadvice may constitute ineffective assistance of counsel even where it is supplied by a paralegal providing scheduling information on behalf of a lawyer. "

2008 U.S. App. LEXIS 3492,
GARFIELD LIVERN ST. VALENTINE ARIS, Petitioner, –v.– MICHAEL B. MUKASEY, Respondent. Docket No. 07-1211-ag
UNITED STATES COURT OF APPEALS FOR THE SECOND CIRCUIT
2008 U.S. App. LEXIS 3492
December 21, 2007, Argued
February 20, 2008, Decided