LOS ANGELES (AP) -- Attorneys for Hunter Biden are expected in court Wednesday in Los Angeles, where he is accused in what prosecutors call a four-year scheme to avoid paying $1.4 million in taxes while living an extravagant lifestyle.

President Joe Biden's son has pleaded not guilty to the nine felony and misdemeanor tax offenses. He's asking the judge to toss out the case, arguing that the prosecution was politically motivated, was tainted by leaks from IRS agents who claimed publicly the case was mishandled and includes some allegations from before he moved to California.

He has also been charged in Delaware with lying on a federal form to buy a gun in 2018 by saying he wasn't using or addicted to illegal drugs, even though he has acknowledged being addicted to crack cocaine at the time. He has pleaded not guilty in that case, which also accuses him of possessing the gun illegally.

Both cases are overseen by special counsel David Weiss and now have tentative trials scheduled for June, though defense attorneys are also trying to get the Delaware gun charges tossed out.

The two sets of charges come from a yearslong federal investigation that had been expected to wrap up over the summer with a plea deal in which Hunter Biden would have gotten two years of probation after pleading guilty to misdemeanor tax charges. He also would have avoided prosecution on the gun charge if he stayed out of trouble.

Defense attorneys argue that immunity provisions in the deal were signed by a prosecutor and are still in effect, though prosecutors disagree.

But the deal that could have spared Hunter Biden the spectacle of a criminal trial during the 2024 presidential campaign unraveled after a federal judge 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 November election draws closer, the Justice Department is actively prosecuting both the Democratic president's son and the presumptive Rupublican nominee, Donald Trump.

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 cases, including that he plotted to overturn the results of the 2020 election, which he lost to Joe Biden.

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. No evidence has emerged to prove that Joe Biden, as president or previously as vice president, abused his role or accepted bribes, though questions have arisen about the ethics surrounding the Biden family's international business dealings.

In launching their Biden impeachment inquiry last year, the House Republicans relied in large part on unverified claims from an FBI informant released by Senate Republicans suggesting that payments totaling $10 million from Ukrainian energy company Burisma to the Bidens were discussed. The now-former FBI informant, Alexander Smirnov, was arrested last month in a case also overseen by Weiss. He has pleaded not guilty to charges that he fabricated the bribery allegations.

If convicted of the tax charges, Hunter Biden, 53, could receive a maximum of 17 years in prison.