President Trump's controversial choice to be the top federal prosecutor in Washington, D.C., Ed Martin, faces an uncertain future, as a Senate Democrat plans to put an indefinite hold on his nomination.

Martin, a "Stop the Steal" advocate and former defense attorney who represented U.S. Capitol riot defendants, is Mr. Trump's nominee to be U.S. attorney for the District of Columbia, and Sen. Adam Schiff, a first-term Democrat from California, plans to hold his nomination amid a growing number of controversial statements and decisions by Martin.

The position is among the highest-profile and most powerful federal prosecutor positions in the U.S. Martin, who refers to himself as "Ed the Eagle," has been serving as acting U.S. attorney for D.C. since Inauguration Day.

Senators have the power to invoke a hold on a presidential nominee, a maneuver that can slow or stall consideration of a nominee for days or weeks. Precious Senate floor time is often needed to overcome holds on presidential nominees.

"For the past nine weeks, Ed Martin has consistently undermined the independence and abused the power of the US Attorney's office in DC, openly threatening and intimidating political opponents, dismissing charges against his own clients, firing public servants for their roles in legitimate investigations and using his office as a cudgel to chill dissent and free speech," Schiff said in a statement to CBS News.