The fuse will soon be lit on what's known as the nuclear option in the Senate to block a filibuster of President Trump's Supreme Court nominee.

FOX's Jared Halpern has more from Capitol Hill:

Oregon Democrat Jeff Merkley spent more than 15 straight hours on his feet on the Senate floor, making his case against Neil Gorsuch:

(Merkley) "It's enormously damaging to confirm a justice when the President's team is under investigation."

Merkley and more than 40 other Democrats are expected to oppose advancing Gorsuch's nomination tomorrow:

(Grassley) "Has poisoned the well of the comity, traditional in the United States Senate."

Judiciary Committee chairman Chuck Grassley calls Gorsuch incredibly qualified.

It will likely trigger what is called the nuclear option, a move by Republicans to unilaterally change existing precedent to lower the 60 vote threshold to a simple majority.

On Capitol Hill, Jared Halpern, FOX News.

Follow Jared Halpern on Twitter: @JaredHalpern