In Concepcion v. United States, the Supreme Court held that a defendant’s Sixth Amendment right to counsel was violated when he was questioned by police without his attorney present after having invoked his right to an attorney during a prior interrogation. The Court found that the government had failed to show good cause for questioning him without counsel and thus violated its obligation under Edwards v. Arizona (1981) not to interrogate defendants who have already requested legal representation in connection with their criminal charges. Furthermore, the Court noted that even if there were some legitimate reason for conducting such questioning, it should have been done in consultation with defense counsel so as not to undermine the defendant's constitutional rights or otherwise prejudice him against self-incrimination. In sum, this case serves as an important reminder of how essential it is for law enforcement officials and prosecutors alike to respect individuals' Sixth Amendment rights when they are charged with crimes and invoke their right to legal representation before being interrogated further by authorities.

In the case of Concepcion v. United States, the Supreme Court was asked to decide whether the petitioner, Concepcion, was entitled to a new trial after his conviction for conspiracy to possess with intent to distribute cocaine. The majority opinion held that the petitioner was not entitled to a new trial because the evidence presented at trial was sufficient to support the jury's verdict. Justice Sotomayor, in her dissenting opinion, argued that the petitioner was entitled to a new trial because the jury instructions given by the trial court were inadequate. She argued that the instructions did not adequately explain the elements of the crime of conspiracy and that the jury was not properly instructed on the elements of the offense. She further argued that the jury instructions did not adequately explain the concept of "intent" and that the jury was not properly instructed on the concept of "intent" as it relates to the crime of conspiracy. Justice Sotomayor argued that the jury instructions were inadequate and that the petitioner was entitled to a new trial. She argued that the jury instructions did not adequately explain the elements of the crime of conspiracy and that the jury was not properly instructed on the concept of "intent" as it relates to the crime of conspiracy. She further argued that the jury instructions did not adequately explain the concept of "intent" and that the jury was not properly instructed on the concept of "intent" as it relates to the crime of conspiracy. She concluded that the jury instructions were inadequate and that the petitioner was entitled to a new trial.