Los Angeles, California - Hunter Biden pleaded not guilty to tax evasion charges when he appeared in federal court Thursday, in a case that adds further pressure on President Joe Biden as he readies for a bare-knuckle election rematch with scandal-plagued Republican Donald Trump.

Hunter Biden is a lightning rod for Republicans, who have hammered the recovering drug addict, alleging – without evidence – that he and his father were partners in a criminal family enterprise.

The younger Biden's appearance in Los Angeles came a day after he turned up unannounced on Capitol Hill, where two Republican-dominated House committees were debating contempt resolutions over his refusal to give closed-door testimony about his business dealings last month.

The 53-year-old was arraigned Thursday on nine counts of refusing to pay federal taxes.

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The indictment, issued on December 7, alleges that money that should have gone to government coffers was instead squandered on funding an "extravagant lifestyle."

Between 2016 and October 2020, "the defendant spent this money on drugs, escorts and girlfriends, luxury hotels and rental properties, exotic cars, clothing, and other items of a personal nature, in short, everything but his taxes," the 56-page indictment says.

Hunter Biden faces up to 17 years in prison if convicted of all the three felonies and six misdemeanors.

He is also under indictment on federal gun charges in Delaware that allege in 2018, he broke laws against drug users having guns.

Last year, a deal that would have seen him plead guilty to two misdemeanor tax counts and acknowledge a firearms violation collapsed amid a firestorm of Republican criticism that the Justice Department was soft-peddling the case out of deference to the president.

Hunter Biden's attorney, Abbe Lowell, said in December that the opposite was true.

"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," he said.

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Republicans and powerful right-wing media outlets like Fox News have made Hunter Biden a bogeyman, repeatedly airing salacious details of his past life as a drug addict and claiming almost daily – without providing evidence – that he engaged in criminal business dealings with his father.

Republicans are using the allegations to underpin an impeachment investigation into the president.

The probe has virtually no chance of ending in a Senate conviction but is serving as a platform to inflict damage on Biden ahead of the November presidential election – and a distraction from Trump's multiple criminal and civil charges, which include an alleged conspiracy to overthrow the 2020 election.