President-elect Donald Trump. (Evan Vucci/AP)

Donald Trump's best day as a presidential candidate — prior to Nov. 8, of course — was May 18, 2016. That was the day Trump released the names of 11 people he would consider for the Supreme Court vacancy caused by the death of Antonin Scalia.

It was a very smart strategy. After all, conservatives had lots and lots of doubts about Trump — and some were even considering a challenge to him at the party's national convention. What he did by releasing those SCOTUS names was remind all of those conservatives of a very simple thing: If I'm president, we could tilt the federal judiciary — from the Supreme Court on down — conservative for a generation or more. If Hillary Clinton is president she could do the same but in the liberal direction.

In his acceptance speech at the Republican National Convention, Trump declared that the Supreme Court “will be one of the most important issues decided by this election.” “The Supreme Court is what it’s all about,” Trump said in the third and final debate with Clinton, a sort of final reminder to conservatives of the stakes in the November election.

Unlike many things that Trump said during the course of the campaign, he wasn't exaggerating about the massive impact he can have on the federal judiciary. The chart below, which comes from the must-have quarterly PowerPoint slide decks of GOP lobbyist Bruce Mehlman, makes that point starkly.

 


And, truth is, Mehlman is almost certainly underselling the number of vacancies that will come up in a Trump administration — particularly on the Supreme Court. Although the Scalia seat is the only one currently open, there are a number of older Justices who have long been rumored as potential retirements: Ruth Bader Ginsburg (age 83), Anthony Kennedy (80) and Stephen Breyer (78). All three are likely to do what they can to stick around until, at least, the 2020 election, but unforeseen circumstances could interfere with those plans.

Although those high-profile openings at the nation's highest court are likely to draw most of the attention, it may be in the lower federal courts where Trump can have the most impact. As WaPo's Bob Barnes and Phil Rucker wrote late last year:

The estimated 103 judicial vacancies that President Obama is expected to hand over to Trump in the Jan. 20 transition of power is nearly double the 54 openings Obama found eight years ago following George W. Bush’s presidency. ...

The result is a multitude of openings throughout the federal circuit and district courts that will allow the new Republican president to quickly make a wide array of lifetime appointments.

It is at those lower levels where a variety of lawsuits on controversial topics such as abortion, gun rights and voter ID will be decided. The decisions by those courts on those matters have the potential to carry impacts that last well beyond Trump's presidency — whether that lasts four years or eight.

If you are looking for where Trump's presidency could matter most, it might not be in the legislative or even the executive branch. It could be the judiciary.