Donald Trump’s surge in the polls has followed the classic pattern of a media-driven surge. Now it will most likely follow the classic pattern of a party-backed decline.
Mr. Trump’s candidacy probably reached an inflection point on Saturday after he essentially criticized John McCain for being captured during the Vietnam War. Republican campaigns and elites quickly moved to condemn his comments — a shift that will probably mark the moment when Trump’s candidacy went from boom to bust.
His support will erode as the tone of coverage shifts from publicizing his anti-establishment and anti-immigration views, which have some resonance in the party, to reflecting the chorus of Republican criticism of his most outrageous comments and the more liberal elements of his record.
His surge in the presidential polls began on June 16 when he declared his candidacy. Announcements of that type always yield a wave of media coverage, just as they did for candidates like Ted Cruz or Marco Rubio. So far this year, media attention from announcements has helped the best-known candidates by an average of six percentage points, with the effect degrading steadily afterward.