Democratic presidential candidate Joe Biden reiterated Friday that he would not comply with a subpoena to testify in the Senate impeachment trial of President Donald Trump, in a new interview with the Des Moines Register’s editorial board.

His comments come as Republicans have threatened to call Democrats — including Biden and his son, Hunter — to testify in a Senate impeachment trial after the House impeached Trump earlier this month, accusing him of abusing his power and obstructing Congress in relation to a Ukraine pressure campaign.