What are blue slips? The century-old Senate tradition Trump wants trashed

WASHINGTON (CN) — President Donald Trump waded into one of the Senate’s most arcane traditions Tuesday, as he called on Republicans to abandon a longstanding procedural mechanism known as the blue slip.

But the president’s GOP colleagues in the upper chamber have so far resisted his calls to do away with the blue slip practice — and they’ve defended the little-known tradition’s value in the judicial selection process.

An informal agreement between senators for more than a century, blue slips have long provided lawmakers a pathway for endorsing or opposing judicial or U.S. attorney nominees who would have jurisdiction over their home states. Quite literally a blue slip of paper, the mechanism can effectively block certain presidential appointments from Senate confirmation.

Carl Tobias, chair of the University of Richmond School of Law, said blue slips were initially intended to help lawmakers, especially those in the Senate minority, protect their constituents from White House nominees that may be bad or unqualified for their positions.

“The major purpose of blue slips is to protect the nomination and confirmation prerogatives of home state minority party senators and the people whom they represent from presidents who might otherwise appoint incompetent or unsuitable prosecutors as the chief federal law enforcement officers in their states for four years, or similarly unfit judges who would enjoy life tenure on the federal bench,” Tobias said.

Under the second Trump administration, Democrats have already employed blue slips against the president’s judicial nominees. Most recently, New Jersey Senators Cory Booker and Andy Kim refused to return blue slips for Alina Habba, Trump’s pick to become U.S. attorney for the District of New Jersey, a move which has indefinitely stalled her Senate confirmation process. Senate Minority Leader Chuck Schumer has also used his blue slip to block former Securities and Exchange Commission chair Jay Clayton’s nomination to a New York U.S. attorney position.

But, like most Senate traditions, the blue slip practice exists at the whim of the majority party — and lawmakers have already demonstrated a willingness to change the precedent to suit their needs.

During the first Trump administration, Iowa Senator Chuck Grassley, then chairman of the Senate Judiciary Committee, announced a so-called “circuit exception” to the blue slip tradition.

Grassley explained at the time that Senate Republicans would no longer honor blue slips from Democrats hoping to block the president’s nominees for appellate courts. He contended that a single senator should not be able to lodge a de facto veto of circuit judges whose jurisdiction usually covers multiple states.

Tobias said that Grassley’s 2017 circuit exception came about because the Senate was “not moving nominees fast enough to suit Trump." The change to the blue slip tradition allowed Trump to set a record for the number of circuit judges confirmed in a president’s first term.

When Democrats wrested control of the Senate in 2020, they similarly refused to honor GOP blue slips for President Joe Biden’s appellate nominees, a move they framed as fairness but which riled Republican senators. That precedent has persisted — the upper chamber still only acknowledges blue slips for federal district court nominees and nominees for U.S. attorneys.

Both Democrats and Republicans have defended blue slips as a mechanism for bipartisan cooperation. Illinois Senator Dick Durbin, who chaired the Judiciary Committee during the Biden administration, said at the time that the tradition was effective in helping to fill judicial vacancies in states with Republican senators.

“[M]embers of both parties can come to the table, quickly fill judicial seats and ensure swift access to justice,” Durbin explained.

And Grassley, once again the top lawmaker on the Judiciary Committee, has vocally backed blue slips during the second Trump administration. During a committee hearing Wednesday morning, he pointed out that while people in “real America” may not care about the arcane practice, it affects the judges and U.S. attorneys appointed to serve in their states.

Tobias opined that the blue slip practice is “one of the last vestiges” of bipartisanship in the Senate.

Despite that, critics of the tradition have argued that it is ripe for abuse. Caroline Fredrickson, a senior fellow at the Brennan Center for Justice, wrote in a 2023 article published in Just Security that blue slips were a “self-imposed soft cap” on the judicial selection process, leveraged by senators to keep judicial vacancies open for political reasons.

“The blue slip is an opaque — and inherently obstructionist — Senate tradition that allows a single senator in any state to block a presidential nominee to the district courts in their electoral patch merely by withholding their consent to consideration of the nominee in committee,” she wrote.

Indeed, under the Biden administration, some Republican lawmakers such as Missouri Senator Josh Hawley refused to engage with the White House on judicial vacancies in their states, leaving those slots open for the second Trump administration to fill.

The president himself on Tuesday accused Democrats of abusing the blue slip tradition, which he called a “hoax” and urged Grassley to abandon the practice. He said in a post on his social media platform Truth Social that the “ancient, and probably unconstitutional” practice ensures that a president can “never” appoint judicial nominees of their choice.

“[I]f you have, even one person in the opposite party serving in the U.S. Senate, he/she must give consent, thereby completely stopping the opposite party’s nomination,” Trump wrote.

Senate Republicans, though, have so far roundly rejected the president’s demands to do away with the blue slip tradition.

Grassley on Wednesday signaled that he had no intention of abandoning precedent. “I was offended by what the president said,” he said. “I’m disappointed that it would result in personal insults.”

The president on Tuesday evening referred to Democratic senators withholding blue slips for his nominees as “sleazebags all.”

North Carolina Senator Thom Tillis, meanwhile, blamed “people in the president’s orbit” for advising him poorly on the blue slip tradition.

“[T]he fact of the matter is, whoever advised him on that policy has no brain on this subject,” he told reporters.

A spokesperson for the White House did not immediately return a request for comment on Senate Republicans’ refusal to abandon the blue slip tradition.

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