Hallie Biden, Hunter Biden's former romantic partner who is the widow of his brother Beau Biden, has taken the stand as the prosecution's next witness.

Prosecutors have said they expect her to testify about Hunter Biden's drug at the time of his gun purchase in October 2018.

Before gun store clerk Gordon Cleveland stepped off the stand, he testified that Hunter Biden did not exhibit any symptoms of drug or alcohol abuse when he purchased the gun at the center of the case.

When asked by defense attorney Abbe Lowell if Hunter Biden exhibited any symptoms at the time of his gun purchase, such as being "glassy eyed" or smelling of alcohol, Cleveland replied, "None at all."

Cross-examining gun store clerk Gordon Cleveland, defense attorney Abbe Lowell asked about the framing of the various questions on the gun form that Hunter Biden is accused of lying on -- including the difference between "have you" and "are you."

The form, for example, asks the applicant if they "have ever" been convicted -- but asks "are you" an unlawful user of drugs.

The defense team has used this to argue that Hunter Biden could have reasonably believed he was not violating any laws when he checked "No" on the drug-use box, because they say he was not currently using drugs.

"It does not say, 'Have you ever,"' Lowell said.

In court today, Hunter Biden has been attentive and focused, watching as attorneys clashed earlier over evidence. He gripped his pen as prosecutor Leo Wise asked the judge to keep out texts that his team wishes to use when they cross-examination Hallie Biden.

Special counsel David Weiss, who brought the case, has been seated in the front row behind his prosecution team, periodically nodding along as they make their arguments.

Gordon Cleveland, the gun store clerk who sold Hunter Biden the firearm at the center of the case, returned to the stand.

Cleveland was being cross-examined by the defense after testifying for the prosecution yesterday.

Hallie Biden, Hunter Biden's former romantic partner who is the widow of his brother Beau Biden, is expected to be the next witness following Cleveland.

Court resumed this morning with a sidebar conference.

Prosecutors and defense attorneys were arguing before the judge about an exhibit the defense wants to introduce when Hallie Biden, Hunter Biden's former romantic partner, takes the stand as expected later today.

Separately, defense attorney Abbe Lowell signaled his intention to file a motion to have the case thrown out after the government rests.

The long-shot bid will be filed on grounds of constitutional shortcomings and insufficient evidence, Lowell said.

Lowell also said his witnesses -- which could include President Joe Biden's brother James Biden and Hunter Biden's daughter Naomi Biden -- may not be available until Friday morning.

Prosecutor Leo Wise, continuing his closing argument, laid out his case for conviction by telling jurors that the evidence in the case was "ugly" but "necessary" to establish Hunter Biden's drug use during the time in question -- as well as in the months before and after.

"He knew he was using drugs," Wise told the jury, a reference to the standard the jury must reach for conviction -- that Hunter Biden had to "knowingly" lie on the gun-purchase form on which he said he was not addicted to drugs.

"That's what the evidence shows," Wise said.

Wise emphasized repeatedly to the jury that the government is not required to show specifically that Hunter used drugs when he owned the gun from the Oct. 12-23, 2018 -- but rather they must "establish that pattern."

To that end, Wise referenced the text messages spanning back to 2015 in which Hunter Biden appeared to purchase drugs or reference his addiction, as well as the testimony from his ex-wife Kathleen Buhle and ex-girlfriend Hallie Biden, who said they either found his drug paraphernalia, saw him use drugs, or talked to him about it.

Wise also pointed to the testimony of ex-girlfriend Zoe Kestan, who testified she saw Hunter Biden using drugs in late September 2018 -- just two weeks before he bought the gun.

"You can convict on that alone," Wise told the jury.

Wise also referenced Hunter Biden's memoir, "Beautiful Things," saying it was a "searingly painful" but "honest" description of himself and his addiction.

The evidence showed Hunter Biden "habitually used," Wise said.