Donald J. Trump clearly has much to learn about being president of the United States.

However, he’s got one task down pat: He has instructed his senior White House staff to utter the same lies the boss does.

Senior policy adviser Stephen Miller was in the dock today, telling TV news talk show hosts the lie Trump keeps spouting about massive voter fraud in the 2016 presidential election.

Miller failed to provide a shred of evidence to prove what he said, which is that vehicle loads of illegal voters were taken to New Hampshire to vote for Hillary Rodham Clinton.

The proof? Miller didn’t provide any. “This Week” host George Stephanopoulos sought repeatedly to get Miller to prove what he alleged. Miller came up empty. He offered nothing.

Indeed, a Federal Elections commissioner has demanded that Trump provide evidence of the allegations he has leveled against state and local elections officials.

Miller has promoted the same falsehoods as the boss. He has continued to delegitimize the electoral process by saying things that either (a) are demonstrably false or (b) cannot be proven.

Absent any proof, many of us are left to conclude that none exists.

Meanwhile, the president continues to perform his role of liar in chief — and his lieutenants are following his shameful example.