In Varela v. Kaiser, 976 F.2d 1357 (10th Cir. 1992), the petitioner entered guilty pleas to five drug charges in an Oklahoma state court. He was later proceeded against for deportation.
On federal habeas corpus, he claimed that his attorney's failure to advise him about the risk of deportation denied him the effective assistance of counsel.
The Tenth Circuit held that the Sixth Amendment guarantee does not include advice as to collateral consequences.
"While the Sixth Amendment assures an accused of effective assistance of counsel in 'criminal prosecutions,' this assurance does not extend to collateral aspects of the prosecution." ...
The circuits that had addressed the issue of failure of counsel to inform an accused of the likely deportation consequences arising out of a guilty plea have all held that deportation is a collateral consequence of the criminal proceeding and therefore the failure to advise does not amount to ineffective assistance of counsel. (976 F.2d at 1358.)