Senator Harry Reid (D-NV) stands during a press conference in April to discuss Supreme Court nominee Merrick Garland. Senate Republicans have refused to hold a hearings on his nomination. (Photo by Allison Shelley/Getty Images)

One issue weighing heavily on Republican minds these days is the Supreme Court seat vacated in February with the passing of Antonin Scalia. In an unprecedented step earlier this year, Senate Republicans refused to hold hearings for Obama nominee Merrick Garland, arguing instead that American voters should have a say in the process by voting in a new president and letting that person nominate the next justice.

Given the likelihood (albeit a slightly diminishing one) of a Hillary Clinton victory next week, Senate Republicans are starting to shift the goalposts by suggesting they might opt to leave Scalia's seat open indefinitely if Clinton takes the White House.

"I promise you that we will be united against any Supreme Court nominee that Hillary Clinton, if she were president, would put up," John McCain told a Philadelphia radio station two weeks ago. McCain's office subsequently toned down his pledge of blanket opposition, but a week later Ted Cruz breathed new life into the idea, telling reporters that there was a "long historical precedent" for having a court with fewer than nine justices.

President Obama urged the Senate to "do their job" and hold hearings on the nomination of Judge Merrick Garland to fill the vacant seat on the Supreme Court. (Reuters)

More recently, North Carolina Senator Richard Burr was even more explicit, telling a private gathering of Republicans in Mooresville, N.C. that "if Hillary becomes president, I’m going to do everything I can do to make sure that four years from now, we're still going to have an opening on the Supreme Court."

An extended vacancy like the one Burr is proposing is absolutely without precedent in the history of the U.S. Supreme Court. The longest Supreme Court vacancy on record is 841 days, or about two years and three months, according to an analysis of historical records conducted by the Pew Research Center. That vacancy opened up in 1844, but as Pew's Drew DeSilver tells it "the mutual antipathy between President John Tyler and the Whig-controlled Senate (the Whigs actually expelled Tyler from their party) made filling the vacancy all but impossible."


Pew Research Center

Back in the 1800s, there were a smattering of Supreme Court vacancies that lasted 500 days or more. But since the turn of the 20th century, such gaps have become unheard of. Since 1900, the longest vacancy lasted 391 days until Henry Blackmun was finally sworn in to replace Abe Fortas in 1970. During that time President Richard Nixon nominated two other candidates to fill the seat, but both were ultimately rejected by the Senate.

The 262-day vacancy for Scalia's seat is now the second-longest Supreme Court vacancy in more than 100 years. But it differs from the Fortas vacancy in one key respect: When Fortas' seat became empty, the Senate held hearings and votes to consider Nixon's choices of successor. Today's Senate has given no such consideration to Merrick Garland.

Ted Cruz is correct that there is historical precedent for a smaller Supreme Court. There were initially only six justices on the bench. Over the years, it grew to accommodate the expansion of the country and the addition of new federal circuit courts.

But the current configuration of nine justices was set by Congress in 1869, and has remained that way ever since. A smaller court -- whether a result of a deliberate Congressional action to reduce its size or as a side effect of partisan obstruction -- would represent a break with nearly 150 years of precedent.