PANTEGO, Texas (CBSDFW.COM) – Republicans and Democrats are gearing up for a political battle once President Donald Trump nominates a new Supreme Court Justice to replace the retiring Anthony Kennedy.

The President will introduce the nominee during a primetime event Monday night.

The candidates for U.S. Senate in Texas, Democratic challenger and congressman from El Paso Beto O’Rourke and Republican incumbent Sen. Ted Cruz, agree the legal and political stakes are high.

“This is a historic moment. This could be the most significant moment of the Trump presidency,” said Sen. Cruz.

“The next justice to be seated on the Supreme Court will decide the most fundamental issues for this country for generations to come,” said Congressman O’Rourke.

But O’Rourke and Cruz disagreed about what factors the president should consider.

CBS News confirmed the president is now focused on three finalists — all of them federal appeals court judges: Amy Coney Barrett, Brett Kavanaugh and Raymond Kethledge.

They are all considered conservatives.

Sen. Cruz told the president he prefers Republican Utah Sen. Mike Lee for the nation’s highest court.

He repeated that during a campaign stop in Rockwall on July 4.

If not Sen. Lee, Cruz shared what he’s looking for: “We want principled constitutionalists on the bench, who are going to follow the law, who are going to respect the Constitution and Bill of Rights, and who are going to uphold our fundamental liberties, our free speech, our religious liberty, our 2nd Amendment, our 10th Amendment.”

O’Rourke told CBS 11 before approving the next Justice, the Senate should know how he or she will interpret what he believes is settled law, including Roe v. Wade.

He said he prefers a justice who treats everyone equally under the law. “In a state like Texas where you can still discriminate based on sexual orientation where we’ve said despite 30,000 kids in the foster care system you can still be too gay to adopt a child in the State of Texas. I want to make sure there’s somebody who’s going to guarantee the law is applied equally to everyone.”

Both Cruz and O’Rourke also disagree about the timing of the confirmation process.

“I imagine we’ll have confirmation hearings in August or September and I fully anticipate the next Justice will be confirmed by the first Monday in October which is the beginning of the next court term,” said Cruz.

“I want to make sure that the Senate has the ability to do its due diligence and we don’t risk this nomination and make sure we can answer these critical questions for something that could not be more important for the future of this country,” said O’Rourke.