Former President Trump adviser Peter Navarro reported to prison in Miami on Tuesday to begin serving a four-month sentence for contempt of Congress.

Why it matters: Navarro is the first high-ranking Trump official to serve prison time over actions related to the Jan. 6 Capitol riot.

• The Supreme Court on Monday rejected Navarro's bid to remain free while he appealed his conviction.

What he's saying: "When I walk in that prison today, the justice system, such as it is, will have done a crippling blow to the constitutional separation of powers and executive privilege," Navarro said during a press conference held near the prison on Tuesday.

• He said he should have been protected from being compelled to testify under executive privilege as a former Trump administration official, calling the case against him an "unprecedented assault on the constitutional separation of powers."

Catch up quick: Navarro was sentenced after defying a 2022 congressional subpoena. He was also ordered to pay a $9,500 fine.

• He's been accused of working to develop a plan to delay Congress' certification of the 2020 presidential election.

Go deeper: Former Trump aide Peter Navarro convicted for contempt of Congress