More and more people are starting to see Trump for what he really is, a sociopath, racist, right wing nut. Nobody wants to see the United States go down in flames under his rule, and nobody wants to see him start a war out of a whim or overreaction from another president saying something that rubbed Trump the wrong way.
Donald Trump was never a serious political candidate, or he would not have alienated the Republican party the way he did. If Trump thought he would actually be President, he would have tried harder in order to get along with leaders in the party who would help him spread his message to others. He doomed his campaign when he came out so abrasive. He hasn't fixed anything either. He complains about babies during campaign speeches and insults women left and right.
Yes, Trump's campaign is doomed without the support of his fellow republicans. Voters look to the guidance and advice of republicans in office and when members of a political party disavow their support for their party's candidate, it raises questions about the candidate's viability and strength as president of the United States.
Donald Trump's campaign is doomed as Republicans disavow him. His own party is rejecting his ideas, and going further by refusing to endorse him and actually stating they will vote for Hillary Clinton. He continues to make controversial statements and shows a lack of basic knowledge of the key issues.