Reid has grown fed-up with Republican obstruction and has growing support within his conference to nuke the minority blocking tactic. He needs 50 Democratic votes to bypass the two-thirds majority required under regular order for a rules change.
Multiple Democratic senators who have traditionally opposed filibuster reform -- including Sens. Patrick Leahy (D-VT), Dianne Feinstein (D-CA) and Barbara Boxer (D-CA) -- have recently come out for a rules change after the GOP's mass blockade of President Barack Obama's three nominees to the powerful D.C. Circuit Court of Appeals, regardless of their qualifications.
Sen. Carl Levin (MI) is the only Democrat on record against invoking the nuclear option.
Reid is set to meet with advocates for filibuster reform Thursday afternoon in the Capitol.
"The obstruction we've seen in the last five years is nothing like we've ever seen before," the majority leader told reporters on Tuesday. "This is not how democracy is supposed to work, or function, and the American people are sick of this."
Don Stewart, a spokesman for Senate Minority Leader Mitch McConnell (R-KY), said that if Democrats pull the nuclear trigger, "it will be a case of the pioneers of judicial filibusters breaking the rules to prevent -- judicial filibusters."
Watch Reid announce the proposed change on the Senate floor.