Hunter Biden pleads not guilty to gun charges

Charges stem from 2018 firearms purchase

Biden accused of lying about drug use on form

He could face up to 25 years in prison if convicted

Biden denies wrongdoing and says he's innocent

Trial is scheduled to begin in 2024

Case has become politically charged

Republicans have accused Biden of special treatment

Democrats defend Biden and say he's being targeted

Case is being closely watched by both parties

Outcome could have implications for 2024 election