Hunter Biden, the son of President Joe Biden, pleaded not guilty in a Los Angeles courtroom on Thursday to nine federal felony and misdemeanor tax offenses.

The charges stem from what federal prosecutors say was a four-year scheme to skip out on paying the $1.4 million he owed to the IRS and instead use the money to fund an extravagant lifestyle that by his own admission included drugs and alcohol.

Hunter Biden has separately been charged in Delaware with lying in October 2018 on a federal form for gun purchasers when he swore he wasn't using or addicted to illegal drugs. He was addicted to crack cocaine at the time. He's also accused of possessing the gun illegally and has pleaded not guilty in that case.

The accusations all come from a yearslong federal investigation into Hunter Biden's tax and business dealings that had been expected to wind down over the summer with a plea deal in which he would have gotten two years’ probation after pleading guilty to misdemeanor tax charges. He also would have avoided prosecution on the gun charge if he stayed out of trouble.

The deal unraveled when a federal judge who had been expected to approve the deal instead began to question it. Now, the tax and gun cases are moving ahead as part of an unprecedented confluence of political and legal drama: As the 2024 election draws closer, the Justice Department is actively prosecuting both the president’s son and Donald Trump, the Republican front-runner.

Hunter Biden’s original proposed plea deal with prosecutors had been pilloried as a “sweetheart deal” by Republicans, including Trump. The former president is facing his own criminal problems — 91 charges across four separate cases, including that he plotted to overturn the results of the 2020 election, which he lost to Biden, a Democrat.

Hunter Biden's criminal proceedings are also happening in parallel to so far unsuccessful efforts by congressional Republicans to link his business dealings to his father. Republicans are pursuing an impeachment inquiry into President Biden, claiming he was engaged in an influence-peddling scheme with his son. Hunter Biden defied a congressional subpoena to appear for closed-door testimony, insisting he wanted to testify in public. He made a surprise appearance at a congressional hearing on Wednesday as House Republicans took steps to file contempt of Congress charges.

No evidence has emerged so far to prove that Joe Biden, in his current or previous office, abused his role or accepted bribes, though questions have arisen about the ethics surrounding the Biden family’s international business dealings.

In an interview that aired Thursday on MSNBC's “Morning Joe,” first lady Jill Biden said she thought the GOP's treatment of her son was “cruel.”

“And I’m really proud of how Hunter has rebuilt his life after addiction. You know, I love my son,” she said. “And it’s had — it’s hurt my grandchildren. And that’s what I’m so concerned about, that it’s affecting their lives as well.”

If convicted of the tax charges, Hunter Biden, 53, could receive a maximum of 17 years in prison. Following the collapse of the plea deal, Attorney General Merrick Garland appointed a special counsel to handle the matter. A special counsel is tapped to handle cases in which the Justice Department perceives itself as having a conflict or where it’s deemed to be in the public interest to have someone outside the government step in.

Hunter Biden's defense attorney, Abbe Lowell, has accused special counsel David Weiss of “bowing to Republican pressure."

“Based on the facts and the law, if Hunter’s last name was anything other than Biden, the charges in Delaware, and now California, would not have been brought,” Lowell has said.