President Trump's expected announcement Tuesday of his choice to fill the ninth seat on the Supreme Court will set in motion a confirmation process that is expected to drag out for at least two to three months, if not longer. Republicans say the duration of what is expected to be a bitter partisan fight will depend entirely on how obstructionist Democrats choose to be. Democrats say the timing depends on how reasonable, or "mainstream," Trump's pick is.

Senate Judiciary Committee Chair Chuck Grassley has said he expects the new justice to be sworn in sometime in April.

But that's if everything goes smoothly.

Two questions will determine the pace of the process: Will Senate Democrats seek to block the confirmation, and if so, what is Plan B for Senate Republicans?

"The Senate should respect the result of the election and treat this newly elected president's nominee in the same way that nominees of newly elected president have been treated," said Senate Majority Leader Mitch McConnell on the floor Monday, already gearing up for the battle. "And that is with careful consideration, followed by an up-or-down vote."

McConnell pointed to two examples under Democratic presidents.

"We had two nominations in the first term of President Clinton — Ginsburg and Breyer," said McConnell. "Both got up-or-down votes. There was no filibuster. We had two nominations in the first term of President Obama — Sotomayor and Kagan. No filibuster. Up or down vote. First-term president."

Five basic steps to get a Supreme Court justice confirmed

Regardless of how rapidly Republicans want to wrap up the process, there are a few steps that must occur at a minimum before any Supreme Court nomination is confirmed. These are the steps Grassley estimates will take at least a couple months.

1. Referral to the Judiciary Committee

After Trump names his choice, the nomination is referred to the Senate Judiciary Committee. The committee has 20 members. There are 11 Republicans and nine Democrats. Because it takes a bare majority of committee members to approve a Supreme Court nominee for a full Senate vote, Democrats lack the votes to block Trump's nominee at the committee level.

2. Prehearing research

Before the confirmation hearing, both Republican and Democratic committee members will conduct research into the nominee's background. The nominee must fill out an extensive questionnaire, which is crafted by the top Republican and Democrat on the Judiciary Committee — Grassley and ranking member Dianne Feinstein of California. Senators will pore over the nominee's past speeches, public statements, press clippings, writings and, if the nominee is a judge, judicial opinions.

Also during this time, the nominee starts making the rounds on Capitol Hill to pay courtesy visits to senators.

3. Confirmation hearing

This hearing can take several days — with at least a couple of days for the Judiciary Committee members to directly question the nominee, and additional days to question outside witnesses. After the proceedings, senators may submit further questions in writing for the nominee to respond to.

4. Committee vote

The committee votes on whether to approve the nominee and then "reports" its "recommendation" to the full Senate.

5. Full Senate vote

The full Senate vote is where things could get dicey for Republicans. Democrats can force Republicans to gather 60 votes in the Senate before the nominee is confirmed. There are 52 Republicans in the Senate. That means Democrats can effectively block — or "filibuster" — the confirmation if fewer than eight Democrats support Trump's pick for the high court.

Next steps for Democrats

There is deep resentment among Senate Democrats about last year's refusal by Senate Republicans to hold any confirmation hearings for Judge Merrick Garland when President Obama nominated him to the Supreme Court. The seat vacated by Justice Antonin Scalia's death has remained unfilled for 11 months.

Senate Democrat Jeff Merkley of Oregon has already vowed to filibuster any Trump pick that isn't Merrick Garland. He told Politico that Republicans are now trying to fill "a stolen seat."

Other Senate Democrats have been less explicit about whether they'd block the confirmation at this point.

Senate Democratic Leader Chuck Schumer has repeatedly said he will oppose against any nominee who is not "mainstream." Other Democrats are echoing that sentiment.

"I just think it should be somebody like Merrick Garland to show, for the first time in the Trump administration, a willingness to be bipartisan for somebody that lost the popular vote," said Democratic Sen. Sherrod Brown of Ohio on Monday.

And Democrats are already signaling that Trump's executive order temporarily banning travel from seven Muslim-majority countries and suspending refugee admission will figure into confirmation hearing.

"A Supreme Court nominee, if willing to respond, should indicate that they regard this executive order as unlawful and unconstitutional," said Democrat Richard Blumenthal of Connecticut, a member of the Judiciary Committee. But Blumenthal added that there was no issue that will determine his position.

Could Republicans go "nuclear"?

President Trump said last week that he thinks Senate Republicans should strip from Democrats the power to block Supreme Court nominees. But McConnell isn't embracing the advice at the moment.

In fact, McConnell has been asked many times about whether he will change the filibuster rules this year — invoking the so-called "nuclear option" — so that it would take only a bare majority of senators to confirm a Supreme Court nominee, rather than the required 60.

In response to this question, McConnell has simply expressed his confidence that Trump's nominee will be confirmed.

When former Senate Majority Leader Harry Reid invoked the nuclear option in 2013 — and changed the Senate rules so it would take only a bare majority of senators to confirm all nominees except Supreme Court picks — Republicans were furious. They called Reid's move foolhardy, pointing out that one day Democrats would suffer the consequences of the rules change when they end up in the Senate minority with a Republican in the White House.

That day has arrived. And now Republicans potentially have the power to further change the rules so the minority can't even block a Supreme Court nominee.

However, it takes 51 votes in the Senate to employ the nuclear option. And Republicans may not have the votes. Already one Republican — Susan Collins of Maine — says don't count on her vote.

"I am not a proponent of changing the rules of the Senate," said Collins on Monday evening. "I hope that common sense will prevail and that we will have a normal process for considering this nominee."

Copyright 2017 NPR. To see more, visit