Hunter Biden is expected to ask a judge at a hearing Wednesday to dismiss tax charges filed against him last year, arguing that the case against him is politically motivated.

Biden alleges prosecutors caved to pressure from Republican lawmakers, who launched an impeachment inquiry into his father, President Joe Biden, after an earlier plea deal fell through.

Hunter Biden’s legal team will challenge the charges in federal court in Los Angeles before U.S. District Judge Mark Scarsi. The judge will hear arguments on several motions filed in recent weeks from both Biden’s legal team, led by attorney Abbe Lowell, and special counsel David Weiss’ office, represented by lead prosecutor Leo Wise.

Scarsi is not expected to immediately rule from the bench on the motions, but he has indicated that he wants the case to move through the pre-trial process as quickly as possible.

Weiss brought nine tax-related charges, including three felony and six misdemeanor charges, against Hunter Biden in a California federal court last year. Weiss alleged that the president’s son failed to pay at least $1.4 million in taxes as part of a multi-year scheme to evade federal taxes, instead opting to “spend millions of dollars on an extravagant lifestyle,” including, according to the indictment, “drugs, escorts and girlfriends, luxury hotels and rental properties, exotic cars, clothing, and other items of a personal nature.”

The president’s son pleaded not guilty to the charges in January. His lawyers filed several motions last month asking the judge to dismiss the charges, arguing that prosecutors had “bowed to political pressure,” among other things.

“The special counsel has gone to extreme lengths to bring charges against Mr. Biden that would not have been filed against anyone else,” Lowell said in a statement when the motions were filed last month. “Prosecutors reneged on binding agreements, bowed to political pressure to bring unprecedented charges, overreached in their authority, ignored the rules and allowed their agents to run amok, and repeatedly misstated evidence to the court to defend their conduct.”

Federal prosecutors pushed back on Hunter Biden’s claims, arguing that he came up with “a conspiracy theory” to dodge tax charges after the earlier plea deal unraveled.

“The defendant concocts a conspiracy theory that the prosecution has ‘upped the ante’ to appease politicians who have absolutely nothing to do with the prosecution and are not even members of the current Executive Branch,” prosecutors wrote in a filing this month.

In addition to the tax charges, Hunter Biden was indicted on federal gun charges in Delaware last year for allegedly possessing a gun while using narcotics. The trial for the gun charges is scheduled for June.

Hunter Biden has become a major figure in House Republicans’ impeachment inquiry into the president. The president’s son gave a closed-door deposition with the GOP-led House Oversight and Judiciary committees last month and railed against the investigation as “charade” in his prepared remarks.