It is such a bad idea. I agree with the two guests, they will not have the numbers to even get people on any of the two houses, least of all the presidency, but instead skew the votes away form Democrats to give an advantage to republicans.
republicans are fanatics, they don't want to hear or learn about anything else but to embrace the hate, corruption, misogyny, racism their party offers, so many of them will, on election day, go to the booth not even knowing a 3rd party exists, they have already checked on every box they see an (R) by the name of the candidate.
These people need to instead put all their efforts into helping Democrats win, save Democracy, get rid of the dirt in the republican party, help fix voting laws and everything republicans have corrupted, then see how you bring a 3rd party into USA politics.
And I dare to say, I believe this country is more progressive than we want to admit. How many hear are against free education, universal health care, women's rights, women getting paid the same as men do for the same job, etc.? Even those who like to criticize Bernie Sanders know that everything he fights for is what the USA should be.