According to the United States Constitution, the President of the United States has the power to grant pardons for federal offenses. However, this power does not extend to convictions in state courts.

The President's pardon power is outlined in Article II, Section 2, Clause 1 of the Constitution, which states that the President "shall have Power to grant Reprieves and Pardons for Offenses against the United States, except in Cases of Impeachment." This means that the President can only pardon individuals who have been convicted of federal crimes.

When it comes to state convictions, the power to grant pardons lies with the governors of each respective state. Each state has its own process and criteria for granting pardons, which can vary significantly. For example, in California, the governor has the authority to grant pardons or commute sentences, while in Texas, the governor can only recommend clemency to the Texas Board of Pardons and Paroles.

Here are a few examples to illustrate the distinction between federal and state pardons:

In 2017, President Donald Trump pardoned Joe Arpaio, the former sheriff of Maricopa County, Arizona, who had been convicted of criminal contempt of court for violating a federal court order. This pardon was within the President's power, as the conviction was for a federal offense.
In 2019, California Governor Gavin Newsom granted pardons to several individuals who had been convicted of state offenses, including drug offenses, firearm offenses, and theft. These pardons were within the governor's power, as they were for state convictions.

It's important to note that while the President cannot pardon state convictions, he or she does have the power to commute federal sentences. Commutation is the reduction of a sentence, either in whole or in part, while leaving the conviction intact. This power allows the President to grant clemency to federal prisoners, even if they were convicted in a state court.

In conclusion, the US President does not have the power to pardon individuals who have been convicted in state courts. The power to grant pardons for state convictions lies with the governors of each respective state. The President's pardon power is limited to federal offenses as outlined in the Constitution.

References:
United States Constitution, Article II, Section 2, Clause 1 - https://www.archives.gov/founding-docs/constitution-transcript#toc-article-ii-
"Presidential Pardons and the Constitution" - https://constitutioncenter.org/interactive-constitution/interpretation/article-ii/clauses/779