Experts Doubt Donald Trump's Plan to Execute Cop Killers Would Pass Muster

— -- GOP presidential candidate Donald Trump reiterated his call for creating a mandatory death penalty for anyone who kills a police officer in the United States, despite possible constitutional conflicts.

“Our police officers have been treated horribly,” Trump told ABC News aboard his private jumbo jet Wednesday. “They've been tremendous supporters of me. … I have great, great feelings for the police of this country. They do a great job and, yes, I want the death penalty for anybody that kills a police officer."

Pressed on how he would accomplish it, Trump said he would "work with the states if I have to; if we can do it on a federal basis, we’ll do it on a federal basis.”

Trump previously raised the issue in the same week he proposed a controversial temporary ban on Muslim Americans entering the United States.

“One of the first things I do in terms of executive order is that if I win, will to be to sign a strong, strong statement that will go out to the country, out to the world, that anybody killing a policeman, a policewoman, police officer. Anybody killing a police officer, death penalty. It’s going to happen,” Trump said earlier this month while receiving as endorsement from the New England Police Benevolent Association in New Hampshire.

Some legal experts are skeptical.

“I really question if he could do something like that,” professor Deborah Denno of the Fordham University School of Law in New said. “There have been only 37 federal executions since 1927.”

Indeed, according to a report released Wednesday by the Death Penalty Information Center, "The national trend towards abolition of the death penalty in law or practice continued: Nebraska legislatively abolished the death penalty; the Connecticut Supreme Court declared its death penalty unconstitutional; and Pennsylvania joined three other states in imposing gubernatorial moratoria on executions.”

Daniel Richman, a law professor at Columbia University in New York, said, “The Supreme Court has been very clear that mandatory death penalties are problematic as a constitutional matter. The whole point of the 8th amendment is to demand a more focused look at the crime and the individual.

“Putting the death penalty part aside, given the Supreme Court’s relaxed commerce clause when it comes to federal criminal law, I suppose such a federal offense could be created if there is, say, a nexus between the gun used in the crime and interstate commerce."