Majority Leader Chuck Schumer announced Wednesday that he’ll use a Senate procedure that allows home state senators to object to judicial nominees to attempt to block President Donald Trump‘s picks for two keep prosecutor positions: the U.S. Attorneys for the Southern and Eastern Districts of New York.

The blue slip process, which has long been honored by the Senate Judiciary Committee, asks for the signoff of home-state senators before proceeding with nominations for U.S. Attorney positions.

Schumer, a New York Democrat, is refusing to return his blue slip for the nominations of Jay Clayton to be the U.S. attorney for the Southern District of New York and Joseph Nocella Jr. to be the lead prosecutor in the Eastern District of New York.

“Donald Trump has made clear he has no fidelity to the law and intends to use the Justice Department, the U.S. Attorney offices and law enforcement as weapons to go after his perceived enemies,” Schumer said in a statement. “Such blatant and depraved political motivations are deeply corrosive to the rule of law and leaves me deeply skeptical of the Donald Trump’s intentions for these important positions. For that reason, I will not return the blue slip for the U.S. Attorney nominees for the Southern and Eastern Districts of New York.”

This blue slip tradition in the Senate is just that: a tradition, not a law.

It will be up to Judiciary Committee Chairman Chuck Grassley whether he ultimately honors this blue slip process in this case.

“The Judiciary Committee has long honored the traditional blue slip process for U.S. Attorney nominees,” a spokesperson for Grassley, an Iowa Republican, told ABC News when reached for comment on Schumer’s intention not to return his blue slip on the two New York U.S. attorneys.

Grassley recently told the New York Times he would honor the right of Senators to refuse return of their blue slips.

“The answer is yes,” Grassley said when asked whether he would honor the blue slip position of senators. “If they are from the state the nomination comes from.”