Republicans will freak out, totally lose their minds and launch a four-year campaign to deride, slander and discredit Sanders or Warren the moment he or she wins the election. They won't wait until the night of the inaugural ball to form their cabal, as they did at the Caucus Room restaurant on the night of January 20, 1009. Their hateful, traitorous obstinance and steadfast determination to wreck the nation will continue unabated until the day that Bernie or Warren leaves office, exactly the way they continue to this day to attack the 44th president of the United States of America.
Don't have any illusions that they will ever back off or even grudgingly acknowledge that a president who is not a slavish tool of their corporate masters could ever do anything right. They will fight to the bitter end to deny him or her anything that the office should entitle him or her to have.