In the case of Iowa v. Felipe Edgardo Tovar, 2003, the U.S Supreme Court ruled that a defendant does not have to be informed about all potential immigration consequences for pleading guilty in order for their plea to be considered voluntary and intelligent under the Sixth Amendment. The court held that while defendants must understand key aspects of the charges against them and possible penalties they face before entering a guilty plea, this does not extend to collateral issues such as deportation. This ruling came after Mr. Tovar pleaded guilty to drunk driving offenses in Iowa but later sought post-conviction relief on grounds his attorney did not inform him about potential deportation risks associated with his pleas.

In the dissenting opinion for Iowa v. Felipe Edgardo Tovar, Justice Scalia argued that the majority's decision expanded upon previous rulings in a way that was not constitutionally justified. He contended that while defendants should be informed of their rights, it is not necessary to provide them with detailed information about every possible consequence and implication of pleading guilty. According to him, this would place an undue burden on courts and could potentially lead to more appeals based on technicalities rather than actual injustices or errors in trial proceedings. Furthermore, he believed that Mr.Tovar had been adequately informed of his rights before entering his plea and therefore did not have grounds for appeal.