MADISON, Wis. — Wisconsin's Democratic U.S. Sen. Tammy Baldwin says her Republican colleague Sen. Ron Johnson needs to decide for himself whether it's appropriate for him to recuse himself if there is a Senate impeachment trial against President Donald Trump.

Johnson has said he will not recuse himself despite his close involvement in Ukraine issues at the center of the investigation.

Baldwin told reporters Monday that Johnson will have to decide if his involvement would violate an oath lawmakers have to take to be impartial if there is an impeachment trial.

Baldwin stood by her position that she has not decided yet whether she would vote to convict Trump, saying she will withhold judgment until she sees all the evidence. The second-term lawmaker also says she's not looking at the "political implications" of impeachment and whether there could be a backlash against Democrats in 2020.