President Trump's long-awaited Senate trial is underway on Capitol Hill. After dispensing of pre-trial procedures last week, the Senate opened Trump's impeachment trial on Tuesday. The trial is expected to wrap up as soon as next week.
Trump was impeached by Nancy Pelosi's House Democrats in December for asking the Ukrainian president to investigate Joe Biden and his son Hunter Biden for corruption and interfering in the 2016 elections.
High-powered attorneys Alan Dershowitz and Ken Starr head Trump's legal team. Starr prosecuted Bill Clinton during his impeachment.
Adam Schiff said Trump has the right to call witnesses, but Schiff warned Trump's high-powered defense team not to call Hunter Biden as a witness.
Schiff, who heads the Democratic managers for the House, insisted that calling Biden as a witness would amount to "abuse".
Republicans accused Biden of using his power to enrich his sons who earned tens of millions of dollars while Biden was vice president to Barack Obama.
"It would not be appropriate for the president to seek to call witnesses merely to try to perpetuate the same smear campaign that was foiled when his plot was discovered," Schiff said in an interview on the CBS Evening News.
"Hunter Biden, for example, can't tell us anything about whether the president withheld military aid, whether he withheld that aid to coerce Ukraine to conduct political investigations or how he wouldn't meet with the president of Ukraine."
Schiff added: That's an illegitimate abuse of the trial. The chief justice, who may have an opportunity to rule on material witnesses, as well as senators should not permit that kind of abuse."