The US Supreme Court is considering whether to extend a rule that requires lawyers to tell clients who are not citizens that they can be deported if they plead guilty to crimes.
A decision could prove significant to immigrants who had ineffective counsel before March 2010 when the court said immigrants deserve to be told at least some consequences of guilty pleas.
Federal appeals courts are divided on whether the decision should apply retroactively.
The case involved Roselva Chaidez, a Mexican citizen and lawful permanent US resident in Chicago.
She disclosed a guilty plea for insurance fraud in 2009 when she applied for citizenship.
Ms Chaidez challenged the government's decision to remove her from the country, saying her lawyer in the criminal case had never told her that she could be deported for pleading guilty.
A lawyer for Ms Chaidez told the Supreme Court that the case confirmed a long-standing rule that criminal defendants deserved reasonably effective counsel who could provide advice.
But Justice Antonin Scalia suggested that that argument was too sweeping because all decisions draw on earlier law.
In contrast, Justice Stephen Breyer suggested that advising clients about the consequences of their actions is what lawyers normally do.
He said: "I would have thought it was common sense that a lawyer would tell a client that terrible things are going to happen to you if you plead guilty."
The federal government countered that the Supreme Court decision did announce a new rule.
It noted that four justices in that case found there was no duty to advise of deportation risk, and that ten federal appeals courts had previously found no such duty.
Twenty-eight US states endorsed that position, fearing demands by thousands of immigrants to withdraw their guilty pleas.
The decision in Ms Chaidez’ case is expected by June 2013 and will likely affect several immigration cases awaiting Supreme Court review.
