President Obama speaks with John Scott Thomson, chief of police in Camden County, N.J., in May. (Reuters/Jonathan Ernst)

President Obama is preparing to reduce sentences for dozens of federal inmates convicted of nonviolent crimes, using his constitutional authority as president to grant clemency to criminals, according to a report in The New York Times Friday.

Gridlock in Congress has led Obama to rely on executive authority to pursue his agenda in other areas as well, notably health care and education. Commutations for any large number of inmates would be another novel use of executive power into a different area of policy, criminal justice.

And they would be another reminder of the obstacles for significant advancement without Congress' input. The several dozen sentences he is reportedly planning to commute is small compared to the hundreds of thousands of inmates in state and federal prisons.

By commuting prisoners' sentences, Obama would also be departing from his own past practice. The president has granted commutations and pardons for a historically small number of applicants.

A pardon eliminates a prisoner's conviction entirely, while a commutation reduces the sentence. Data from the Justice Department show that each recent president has received applications for one or two thousand pardons, along with a steadily increasing number of commutations - 892 under President Nixon, 8,576 under President George W. Bush and 16,911 under Obama as of last month.

That last figure could be much higher. Peter Baker reports in The Times that more than 30,000 prisoners have applied in response to a call from the Justice Department.

Typically, presidents have been more likely to grant pardons than commutations. One possible explanation could be that only those with the strongest cases for clemency bother applying for a complete pardon as opposed to a commutation.

Obama, however, has been less likely than his predecessors to grant pardons and commutations. He has approved just 3 percent of the applications for pardons and 0.3 percent of those for commutations.

The main reason that Obama has granted such a small percentage of the commutations is that he has received far more requests than any other president. He has already granted 43 commutations, a historically high number. If he commutes several dozen sentences, he could easily issue more commutations than any president since Lyndon B. Johnson, who issued 226.

Those figures, along with the Justice Department's invitation to inmates to seek commutations, mark a change in how Obama is using his power to grant clemency, compared to what his predecessors did.

Earlier in his presidency, Obama signed a law reducing sentences for those convicted of possessing crack cocaine. His former attorney general, Eric Holder, also issued guidelines instructing prosecutors not to seek excessively long terms for those accused of drug crimes.

These changes, however, affect only a small number of the nation's prisoners. Federal drug offenders make up about 4 percent of the incarcerated population on any given day, according to data complied by the Prison Policy Initiative in Northampton, Mass.

Correction: An earlier version of this item incorrectly stated that President Truman had granted more commutations than any president since. President Johnson granted more. Truman issued 118, and Johnson issued 226. We regret the error.