Yes. The Sixth Amendment guarantee of effective assistance of counsel is a fundamental right essential to a fair trial. The specific procedures required to complete a guilty plea in open court are a type of trial.
Courts are reluctant to accept a plea of guilty from a Defendant whom is not represented by counsel because these cases may later be challenged on appeal. A guilty plea waives all but jurisdictional defects and challenges to the plea itself. Commonwealth v. Faniel, 412 Mass. 497 (1992). Failure to warn of this consequence has resulted in reversals.
You need the effective assistance of a lawyer when deciding whether or not to plead guilty. Without consulting with a competent attorney, you are risking a wrongful conviction.
If you plan on pleading guilty to any crime with a potential penalty of any jail time, you need the effective assistance of a lawyer. A prudent counselor must actively participate in the investigation of the facts, evaluate those facts as applied to the current state of the law, advise the client accordingly, advocate for a charge concession by the prosecution, and argue for a lesser punishment at sentencing.
If you are not a citizen of the United States, the acceptance by a Court of your plea of guilty, plea of nolo contender, or admission to sufficient facts may have consequences of deportation, exclusion from admission to the United States, or denial of naturalization, pursuant to the laws of the United States.
If the offense to which you are pleading guilty, nolo contender, or admitting to sufficient facts is under federal law one that presumptively mandates removal from the United State and federal officers decide to seek removal, it is practically inevitable that this disposition would result in deportation, exclusion from admission, or denial of naturalization under the laws of the United States.