There is a sound basis for the collateral consequences doctrine. Neither courts nor defense counsel can be expected to be aware of the multitude of potential consequences that may flow from a conviction. Courts do not always agree upon whether a particular consequence is collateral or direct, but generally speaking, those consequences that do not flow directly from the sentence are considered collateral. Several opinions and commentators have catalogued examples of collateral and direct consequences. The majority of courts that have decided the issue in the post-conviction context have concluded that counsel is not ineffective for having failed to advise the defendant about deportation.
Most courts do so on the basis that deportation is a collateral consequence.
Some courts, while holding that an attorney's failure to advise a defendant about potential deportation is not ineffective assistance of counsel, pronounce that it is preferable that defense counsel give advice about potential deportation. Although the majority of courts do not find ineffective assistance of counsel for failure to advise a defendant about deportation, there are a number of courts that do. Some take the position that an affirmative misrepresentation by counsel on the deportation consequences of a conviction is ineffective assistance of counsel. Other courts conclude that failure to advise an alien defendant on possible deportation consequences can be ineffective assistance of counsel. The court held that potential deportation consequences are material and the failure to investigate those consequences, when the attorney knows that the defendant is an alien, constitutes ineffective assistance of counsel.