WASHINGTON — Ohio Republican Rob Portman, a leading figure in his party who is sometimes mentioned as a candidate for president in 2016, will call for a reevaluation of the "war on drugs" and the massive prison population it has created in a speech set for Tuesday and shared exclusively with BuzzFeed.

But Portman is also expected to warn that President Obama's plan to use executive power to make reforms to drug sentencing could prevent larger, lasting changes from coming to pass.

"President Obama recently announced that he would grant clemency to hundreds of non-violent drug offenders," Portman is set to say Tuesday in a speech at the American Enterprise Institute. "That may be within his power, but it's like placing a Band-Aid on a deep wound. It may cover up the problem of prison overcrowding today, but it doesn't address the deeper problem that drives recidivism."

Portman's words come as crime, punishment, and drugs emerge as a rare and unlikely point on which Democrats and Republicans in Washington are finding common ground. Conservatives like Portman, troubled by the vast federal spending on jails and seeking a distinctly conservative approach to crime and poverty, have found allies in Democrats and civil libertarians who have long argued for a less punitive approach to illegal drugs.

Portman's speech lays out a plan to fight poverty using what he calls "constructive conservatism." In the speech, the Republican senator describes that as a "bottom up" approach that lets communities develop plans to fight poverty, prove their results and then spread those ideas across the country with the help of federal grants and other assistance.

The possibility of bipartisan action on criminal justice reform drives the sections of Portman's speech related to the war on drugs and the prison population. In the prepared remarks, the Ohio Republican calls for a reauthorization of the Second Chance Act, aimed at reducing the recidivism rate with job training, drug counseling and other programs he first wrote with a Democrat 10 years ago. Vermont Democratic Sen. Patrick Leahy is co-sponsoring the bill this time around, and Portman will highlight in the speech a second bill called the Recidivism Reduction and Public Safety Act (co-sponsored by Rhode Island Democrat Sheldon Whitehouse) that aims to bring the Second Chance act reforms to the federal prison system.

The reform talk in Portman's speech puts the Ohio Republican in a leading role in the growing conservative push for prison and criminal justice reform. Portman and other Republican reformers are calling on conservatives to embrace spending on efforts like the recidivism reduction programs in the hopes that in the long run they'll reduce prison populations and save billions in incarceration costs.

In the AEI speech, Portman will become one of the most prominent elected Republicans to criticize the "war on drugs," a metaphor dating back to the Nixon Administration, and a phrase the Obama Administration refuses to use. Portman said the effort has spent a lot of money but done little to solve the problems of drugs and poverty.

"After more than a trillion dollars spent in the war on drugs and thousands of lives lost, we are starting to understand that arrest, prosecution, and incarceration are not enough," he will say in the prepared speech.

"You cannot talk about poverty without talking about addiction, and addiction is something that a war on drugs is never going to solve," Portman is set to say.

Portman will say Obama could play a part in these reforms, but warns the president's emphasis on executive action is problematic when it comes to bipartisan reform efforts.

"Instead of taking the easy path of executive action, I would ask the president to come to Congress and work with us to pass our legislation to reform federal prisons, leveraging our criminal justice system to incentivize long-term solutions based on what we know works to help people get out of prison and stay out, things like diversion programs and drug courts, job training, and treatment for addiction and mental services," Portman will say.