The Trump administration is pushing for legislation that would accelerate certain federal death penalty cases.

The new legislation is expected around Labor Day, according to Attorney General William P. Barr, and will specifically expedite the use of the death penalty for offenders who murder police officers or commit mass murders.

Speaking before the Fraternal Order of Police's biennial conference on Monday, Barr told the assembled officers that his office was well aware of a recent increase in assaults on police officers, and emphasized that the administration "will not tolerate violence against police."

"We were all nauseated by the spectacle of prancing punks pelting New York police officers with water and plastic buckets," Barr said, according to his released remarks. "Unfortunately, these were not isolated events. From 2014 through 2017, there has been a 20 percent increase in assaults against police, up to about 60,000 per year."

This is why, according to Barr, the White House expects to roll out its new proposal for an expedited death penalty for cop killers.

"We will be proposing legislation providing that in cases of mass murder, or in cases of murder of a law enforcement officer, there will be a timetable for judicial proceedings that will allow imposition of any death sentence without undue delay," the attorney general said. "Punishment must be swift and certain."

Barr's announcement follows his official reinstatement of the federal death penalty in July, following nearly two decades of a de facto pause. The first of the five executions initially ordered by Barr are expected to take place later this year, reflecting President Donald Trump's staunch support for the death penalty.

In addition to expedited executions for mass murderers and cop killers, Trump has also called for death eligibility for federal hate crime offenders—presumably only those who commit homicide, as the death penalty is generally not applicable to non-homicide offenders. It is unclear if the hate crime provision—widely perceived as a response to the recent racially-motivated shooting at an El Paso Walmart—will be part of the administration’s new legislation.

At the same time, the proposal to implement a fast-track for certain death-eligible offenders is likely to attract both attention and court challenges. The details of what, exactly, Barr means by a "timetable of judicial proceedings" remains unclear, but expedited proceedings tend to draw criticism from opponents of the death penalty, who see them as a threat to due process. At the same time, the length of post-conviction appeals in death penalty cases have ballooned. The individuals executed in 2017 had spent an average of more than 20 years on death row prior to their executions, according to the Bureau of Justice Statistics.