From the start, Senate Republican leaders have known their ambitious timeline to get Supreme Court nominee Amy Coney Barrett confirmed before Election Day offered little room for error.

But that tightly crafted schedule has now been thrown into uncertainty with the coronavirus diagnoses of at least two Republicans on the Senate Judiciary Committee and the fear that other senators could test positive in the coming days. A handful of other GOP senators, on and off the committee, are also isolating as a precaution after being exposed to infected colleagues.

Sensing an opportunity to delay, Democrats are cranking up their push to postpone the Oct. 12 confirmation hearings, citing the safety of members, aides and Barrett herself — waging a public pressure campaign because they have no powers on their own to stop the proceedings.

In a statement to The Washington Post on Sunday, Senate Minority Leader Charles E. Schumer (D-N.Y.) demanded that Sen. Lindsey O. Graham (R-S.C.) require all members of the Judiciary Committee to be tested before participating in Barrett’s confirmation hearing. Democrats have also insisted that remote participation, even for senators, is inadequate for a lifetime appointment to the Supreme Court.

“Moving forward with the committee process when three senators have recently tested positive for covid-19 is irresponsible and dangerous, but doing so without requiring all members to be tested before a hearing in accordance with CDC best practices would be intentionally reckless,” Schumer said in the statement to The Post. “If Chairman Graham doesn’t require testing, it may make some wonder if he just doesn’t want to know the results.”

Aides to Graham did not immediately return a request for comment Sunday. Democrats are also eyeing their real opening: when GOP votes are needed to advance Barrett’s nomination in the committee and on the floor and a critical mass of Republican senators may remain positive for the novel coronavirus or in isolation when their in-person presence would be needed.

Of the dozen GOP senators on the committee that will take up Barrett’s confirmation, two — Sens. Mike Lee (Utah) and Thom Tillis (N.C.) — announced Friday that they had tested positive for the coronavirus. Two others — Ben Sasse of Nebraska and Ted Cruz of Texas — have tested negative but are self-quarantining upon medical advice and, in Sasse’s case, will undergo more tests.

All four have said they plan to return to Washington by Oct. 12, although Graham has offered any member the opportunity to participate remotely if necessary. A handful of other Republicans on the Judiciary Committee, particularly those at a Rose Garden ceremony for Barrett on Sept. 26 that more than a half-dozen infected people attended, have tested negative.

The third Republican senator known to currently have the virus is Sen. Ron Johnson (R-Wis.), while others, such as Sen. James Lankford (R-Okla.), are self-quarantining as a precaution after being exposed to other senators who tested positive.

Well before the news that Lee and Tillis had tested positive, the Judiciary Committee had been preparing for one of the most high-profile hearings any Senate will hold, yet under the most unusual of circumstances.

Barrett plans to testify in person, according to a Republican aide involved in the hearing logistics who spoke on the condition of anonymity to freely discuss private planning. Supreme Court confirmation hearings are usually held in a mammoth room in the Hart Senate Office Building, but congressional officials are imposing much stricter requirements to try to maintain a safe environment for Barrett, her family, senators, aides and the media.

In the Hart hearing room, there is typically one long dais for senators, but a second will be constructed in front of the existing one to allow for more space between each lawmaker. Each senator — as well as Barrett — will have his or her own sanitary station equipped with hand sanitizer, wipes, paper towels and trash cans. Several stations with personal protective equipment such as masks and gloves will be scattered throughout the room, while the committee will strictly enforce a one-aide-per-senator rule inside the hearing room, requiring staffers to show a shared badge to enter the room.

On the floor of the hearing room, there will be about 10 seats available for the media — in contrast with the 108 people credentialed for the first day of the confirmation hearings for Brett M. Kavanaugh two years ago. There will be space for Barrett’s family, who will remain in a little “bubble” together, as well as about five officials from the administration or those there to introduce her.

There will be no members of the public allowed into the hearing room. Unless they have an escort, members of the public have not been allowed into the Capitol complex since the spring.

“The one thing I want people to know is that the virus is serious, but we have to move on as a nation. When a military member gets infected, you don’t shut down the whole unit,” Graham said during a debate Saturday against his Democratic challenger, Jaime Harrison. “We’re going to have a hearing for Amy Barrett, the nominee to the Supreme Court. It will be done safely — but I’ve got a job to do, and I’m pressing on.”

Despite the outcry from Democrats that a remote hearing for Barrett is insufficient, the Judiciary Committee alone has held 21 hearings that had some sort of virtual component since the pandemic surged this spring, according to research compiled by Senate Republicans. That includes a May 6 confirmation hearing for Justin Walker to the U.S. Court of Appeals for the District of Columbia Circuit, in which four Democratic senators and two Senate Republicans appeared via video.

It also includes a May 20 confirmation hearing for Cory Wilson to the U.S. Court of Appeals for the 5th Circuit in which three Senate Democrats and one Republican senator questioned him remotely. Both Wilson and Walker — who were confirmed to lifetime judicial appointments — appeared in person.

Sen. Amy Klobuchar (D-Minn.), a member of the Judiciary Committee who also is the ranking Democrat of the panel that oversees Senate operations, acknowledged Sunday that it was “important” to give senators the option of a hearing conducted virtually.

But on a Supreme Court confirmation, “you want to be able to go back and forth with this nominee,” Klobuchar said on “Fox News Sunday.”

If more of his members continue to fall ill or are forced into isolation, the math for Senate Majority Leader Mitch McConnell (R-Ky.) is virtually impossible to overcome. That is especially the case if Democrats — who have adhered to stricter guidelines than Republicans, meeting virtually for party lunches rather than in person like GOP senators do — remain healthy and present.

McConnell has already lost the support of Sens. Susan Collins (R-Maine) and Lisa Murkowski (R-Alaska), although only Collins has explicitly said she would vote against Barrett on the floor should a vote be held before the election.

The first obstacle for Republicans may be the committee vote, tentatively planned for Oct. 22.

To report out a nomination, a majority of the 22-member committee will need to be present, and Democratic senators will not help Republicans make quorum, aides said Sunday. Although proxy voting is allowed in the Judiciary Committee, it works only when there is a quorum present and the proxy votes don’t change the outcome of the vote, according to committee officials.

That means absences on the GOP side would greatly complicate the prospects of holding a successful committee vote for Barrett. McConnell can take procedural steps to bring Barrett’s nomination to the floor without any committee vote, but that would require the consent of 60 senators, according to Democratic officials who have reviewed the floor procedure.

Outside advisers working on the confirmation have suggested a system in which the committee vote would be held in the Senate chamber, with ill senators voting from the visitors’ galleries above the floor so they can maintain distance. Yet GOP aides have yet to discuss that option.

For now, Republicans are promising to press forward — virus or not, healthy or infected.

“I think every senator who has currently tested positive or is in isolation will be back to work, under normal conditions” by later this month, Sen. Tom Cotton (R-Ark.) said Sunday on Fox News. But if not, Cotton said “there is a long tradition of . . . ill or medically infirm senators being wheeled in to cast critical votes on the Senate floor.”