WASHINGTON — At the White House press conference on Monday, I asked President Donald Trump and Senate Leader Mitch McConnell about “blue slips,” the tradition now at risk granting home state senators — for us that would be Democrats Dick Durbin and Tammy Duckworth — the ability to veto White House judicial nominees.

This matter of “blue slips” may seem like inside Congress arcane stuff to you — I get it — but it’s a big deal for the Chicago-based 7th U.S. Circuit Court of Appeals with two Illinois vacancies pending created by the retirements of Judges Richard Posner and Anne Williams. Williams is taking senior status, which lets her still deal with some cases.

Who fills those lifetime appointments will have an impact on our city and state.

The 7th Circuit includes Illinois, Wisconsin and Indiana. Under a Senate tradition that is about 100 years old, home-state senators have to give their approval — through signing a “blue slip” — to clear the way for the Senate Judiciary Committee to even consider a nominee. Posner and Williams hold “Illinois” seats on the 7th Circuit; that’s why the Illinois senators come into play.

Sen. Chuck Grassley, R-Iowa, chairs the Judiciary Committee and he has not announced yet if he will continue to honor “blue slips” for judicial nominees. Grassley’s reluctance to say what he will do has stirred a controversy.

As Sen. Dianne Feinstein, D-Calif., the top Democrat on the Judiciary Committee wrote in an Oct. 12 op-ed in the Washington Post, “Republicans have long been on board with this tradition. In 2009, the entire Republican conference wrote to President Barack Obama, telling him they had to be consulted and would use the blue-slip process to block any nominees from their home states they didn’t approve of.”

If the blue slip rule was dropped, Feinstein wrote, Republicans would “hope to stack the nation’s courts with young, ideological judges who could radically affect civil rights, women’s rights, workers’ rights and the ability to check the ever-growing power of corporations over Americans.

“Removing the only tool that prevents President Trump from choosing anyone he wants to sit on our federal courts could further weaken the judiciary’s ability to serve as an independent check on the executive branch.”

I recently asked Durbin, a member of the Senate Judiciary Committee, about his concerns in filling the Posner and Williams vacancies.

Keep in mind because of the power of the blue slip, the Trump White House, Durbin and Duckworth all worked together to produce a nominee for Chicago-based U.S. Attorney for the Northern District of Illinois, John Lausch.

Indeed, the Judiciary panel will take up the Lausch nomination on Thursday, where is he likely to approved on a voice vote and have his name advanced to the full Senate, where he is all but certain to be confirmed.

“It gets down to basics, and that is, who will they nominate,” Durbin told me. “Will this person be moderate, extreme, qualified or not?”

Before Lausch was nominated, Durbin and Duckworth interviewed him. “We did due diligence on him before he was announced. . . . It’s easier if they give us a heads up . . . so there is no embarrassment if we say no, and we give a timely response, so if there is a problem, they know it.”

With this in mind, I asked Trump and McConnell what they wanted to do with blue slips — the tradition that gives Democrats leverage over the appointments.

Trump turned over the podium to McConnell, who wants to end to the judicial “blue slip” blackball.

“So my own personal view is that a blue slip on a circuit judge should simply be a notification of how you intend to vote,” McConnell said.

I pressed Trump for a reply. Said Trump, “We could talk blue slips, but my attitude is, I just want really capable people going to the courts.”

It’s not clear that Trump realized that keeping blue slips means giving home-state senators — even if they are Democrats — a say in the pick.

Recently, I asked a White House spokesman how they were going about looking to fill the Illinois vacancies. For now, the posture is to cooperate with Durbin and Duckworth.

“For the vast majority of the blue slip’s history, it has been a consultation requirement,” said Kelly Love. “In every state, we have done everything we can to consult home state senators in good faith before nominating candidates, in accordance with that longstanding tradition. We are following the same practice of extensive, careful consultation in Illinois.”