Remember, Republicans know this to be the case when they're crying about "activist judges". They know full well what the law is.
They're lying freely not because they believe what they're saying, but because they need what they're saying to be true in order to justify what they're planning.
It's also "the big lie". Repeat it over and over and over, and people will believe it. Especially low information people, and those who believe what he says without bothering to confirm in any way.