Justice Samuel Alito, the second-oldest justice and one of the most conservative, joined the high court 20 years ago.

President Donald Trump’s administration is stepping into high-profile appeals at the Supreme Court without invitation at an unprecedented pace, supporting conservative groups in cases dealing with guns,

So far, the high court’s conservative supermajority has largely indicated that it is “not eager to curb the Trump administration,” said Daniel Farber, a law professor at University of California, Berkeley. “That’s why I think the tariff case is so significant. It’s our first real chance to see if they are going to try to draw some lines.”