Vice President Pence argued the case for Supreme Court nominee Neil Gorsuch during a Philadelphia appearance Saturday, calling confirmation of the appeals court judge essential to "reaffirming the primacy of our Constitution."

Speaking to about 120 members of the conservative Federalist Society in Congress Hall, Pence vowed to keep Senate Democrats from blocking Gorsuch's confirmation with a filibuster, ensuring an up-or-down floor vote "one way or another."

It was a reference to President Trump's recent calls for Senate Republican leaders, who have the majority in the chamber, to change the rules and strip Democrats' right to use the parliamentary stalling tactic. In Washington, that's known as the "nuclear option."

Using the filibuster to stop Gorsuch would be an "unwise and unprecedented act," Pence said, noting that no nomination to an associate justice seat on the high court has been defeated with the maneuver. He quoted Democratic admirers of the judge and pointedly reminded his audience that the Senate had confirmed Gorsuch to the 10th Circuit Court of Appeals in Denver by acclamation.

"This seat does not belong to any party or ideology or interest group. This seat belongs to the American people," Pence said. He argued Trump was elected "in significant part" because of his promise to appoint conservative judges.

Gorsuch, the vice president said, is an "originalist" who applies the law and Constitution as written, instead of creating new law. That is a significant goal of the Federalist Society, an organization of conservative lawyers and legal academics who believe in traditional jurisprudence, the separation of powers, and limited government. Pence was speaking to the Philadelphia chapter of the group.

Pence said the nominee was in the mold of Justice Antonin Scalia, whose death last February created the vacancy Gorsuch would fill.

But a fierce battle looms in the Senate. Democrats are bitter that the GOP majority refused for 11 months to consider President Barack Obama's nomination of U.S. Circuit Judge Merrick Garland to the vacancy. If Democrats use the filibuster, Republicans would need to muster 60 votes to cut off debate and bring Gorsuch to a vote.

Senate Majority Leader Mitch McConnell (R., Ky.) has not ruled out the "nuclear option" to take away the tactic. If that were to happen, Gorsuch could be confirmed by a simple majority. Republicans have 52 members in the 100-seat body.

A recent Gallup Poll found Americans generally positive about the Gorsuch pick, with 45 percent saying he should be confirmed, though pollsters said that was lower than the initial support for other nominations in recent years.

It was in another politically tumultuous time -- from 1790 to 1800 -- that the new nation's legislature met in Congress Hall, the House on the first floor and the Senate upstairs. In the airy House chamber where Pence spoke, George Washington stepped down and his successor, John Adams, was sworn in, marking the first peaceful transfer of power in the United States.

The farewell address Washington gave there became a classic. He warned that excessive political partisanship, "the spirit of party," regional jealousies, and foreign entanglements were threats to the unity of the nation.

"It is of infinite moment that you should properly estimate the immense value of your national union to your collective and individual happiness; that you should cherish a cordial, habitual, and immovable attachment to it; accustoming yourselves to think and speak of it as of the palladium of your political safety and prosperity," Washington said, speaking to his successor and lawmakers.

As he spoke, of course, partisan feelings were hardening. Adams was a Federalist, and his rival Thomas Jefferson, who became vice president that day, a member of the Democratic-Republican Party.

Before Saturday's event, Pence visited the Liberty Bell and taped an interview with George Stephanopolous for ABC's This Week Sunday program.

"We didn't get to see anything" when he and Trump were in Philadelphia on Jan. 26 for the Republican congressional retreat, Pence said at the bell pavilion.

Park Ranger Larry McClenney began to explain the bell's inscription, which was taken from Leviticus 25:10, and Pence recited the verse before the ranger could finish. "Proclaim liberty throughout all the land unto all the inhabitants thereof," Pence said. "I've quoted it many times. I love it."

On the way to his motorcade, Pence could not resist one more stop -- Independence Hall. As another ranger began the story of the only original piece of furniture in the room, the vice president interjected that it was the chair inscribed with a rising sun, which Washington sat in to preside over the Constitutional Convention in 1787.

"I was an American history major in college," Pence explained to reporters. "It gives me chills to be in here, as I think it does every American."