> If Congress passes a law that say "tobacco is banned", and the US President says "I will direct my agencies to follow this new law" and you have agencies saying "I'm not a lawyer, but I feel like this law is unconstitutional so my agency is not going to follow it!"?

Now if Congress passes a law that say "tobacco is banned", the president can say "This law means that tobacco isn't banned and has to be sold in schools, and I will direct my agencies to follow this new law". Before, the president had the option to refuse to enforce the laws as written (and risk getting thrown out on his ass) and now the president has the option to rewrite laws according to his whim and enforce that instead. He also has immunity too so he can't even get into trouble for just doing whatever he wants.