Sanford: 'I don't know' if I would vote for Trump in 2020

Former South Carolina Rep. Mark SanfordMark Sanford5 lawyers leave Trump impeachment team ahead of trial: reports South Carolina GOP votes to censure Rep. Rice over impeachment vote Trump selects South Carolina lawyer for impeachment trial MORE, a Republican challenging President TrumpDonald TrumpNoem touts South Dakota coronavirus response, knocks lockdowns in CPAC speech On The Trail: Cuomo and Newsom — a story of two embattled governors McCarthy: 'I would bet my house' GOP takes back lower chamber in 2022 MORE in a longshot primary campaign, said on Sunday that he isn't sure if he would still consider voting for Trump in 2020, despite allegations that the president solicited foreign interference to benefit him politically. 

Host Jake TapperJacob (Jake) Paul TapperEx-Trump press secretary criticized for stirring up QAnon on Twitter Maryland GOP governor says he would have voted to convict Trump Democratic senator defends decision not to call witnesses: 'They weren't going to get more Republican votes' MORE asked Sanford on CNN's "State of the Union" if he would vote for Trump over Vice President Joe BidenJoe BidenNoem touts South Dakota coronavirus response, knocks lockdowns in CPAC speech On The Trail: Cuomo and Newsom — a story of two embattled governors Biden celebrates vaccine approval but warns 'current improvement could reverse' MORE if they end up being the candidates in 2020. 

"I don’t know," Sanford responded. "What I've said is I'm an issue guy." 

Sanford said he's going to base his decision on "who is going to be closest to me" with a focus on debt and spending. 

Former Illinois Rep. Joe WalshJoe WalshGOP lawmakers mourn death of Rush Limbaugh Sacha Baron Cohen pens op-ed on the dangers of conspiracy theories Sunday shows preview: Protests continue over shooting of Blake; coronavirus legislation talks remain at impasse MORE, a fellow 2020 GOP challenger, said there is "no way in hell" he would vote for Trump.

"I'm running against President Trump because he's unfit," Walsh said. 

"The debate is about Trump, period," he added. 

The Republicans were also split on where they stand on impeachment, with Walsh saying the president deserves to be impeached based on his public actions alone and Sanford saying Congress needs to follow a formal investigation process. 

Trump is facing an impeachment inquiry after a whistleblower came forward with allegations that Trump asked Ukraine to investigate Biden and his son. 

A partial memo of a call between Trump and Ukrainian President Volodymyr Zelensky shows Trump asking the foreign leader to investigate the Bidens. 

Trump publicly called on China and Ukraine to investigate the Bidens when speaking to reporters last week.