Electorate vs "alternate" electors

*Kamala Harris said in a campaign video that former President Donald Trump’s pick for vice president will be "loyal only to Trump, not to our country."*

She had a firm basis to make this claim: Vance said, "If I had been vice president, I would have told the states, like Pennsylvania, Georgia and so many others, that we needed to have multiple slates of electors and I think the U.S. Congress should have fought over it from there."