A more thorough explanation:

A concurrent sentence is a type of sentence that a judge can give to a defendant who has been convicted of more than one crime. Instead of serving each sentence one after another, the defendant can serve all of their sentences at the same time, with the longest sentence controlling the length of the overall sentence.

For example, if someone is convicted of two crimes and one sentence is for 5 years and the other is for 10 years, they would serve a concurrent sentence of 10 years, rather than serving 5 years for one crime and then 10 years for the other crime.

In some cases, a judge may not have discretion in deciding whether to give a concurrent or consecutive sentence because a state law may require a consecutive sentence. However, in most cases, judges have the discretion to decide what type of sentence to give.

For instance, in Oregon v. Ice, the Supreme Court held that states could give judges the discretion to decide whether a convicted defendant will serve a concurrent or consecutive sentence. A few years later, Congress passed 18 U.S. Code § 3584, which provides judges with the discretion to decide whether sentences will run consecutively or concurrently.

The statute also provides a list of factors that judges should consider when determining what sentence to give defendants. For example, if a person is convicted of attempting to commit a crime and actually committing the crime, then the judge will be restricted from giving the defendant a consecutive sentence.

Overall, a concurrent sentence allows a defendant to serve all of their sentences at the same time, which can be beneficial for the defendant because they will spend less time in prison. However, judges must consider the seriousness of the crimes and other factors when deciding whether to give a concurrent or consecutive sentence.