How will Donald Trump’s positions and rhetoric be treated by journalists who think of themselves as nonpartisan and subscribe to these professional norms? The big thing determining if his assertions are treated as in the sphere of controversy or rejected as belonging to the sphere of deviance is whether other prominent Republicans support him on a daily basis.

If they do, journalists will feel obligated to treat Trump as a normal candidate. They will cover both sides of the issue equally — such as whether Mexican immigrants are rapists, if Trump can build a wall and get Mexico to pay for it, or if the US should ban all Muslim immigration. Trump’s view would be the treated as the Republican position and the other side as the Democratic position….

If national Republicans refuse to support (and often criticize) Trump’s campaign messages, it makes it easy for national reporters who aspire to be nonpartisan not to give Trump and his critics equal billing. There will likely be much more space given to Trump’s opponents than to his campaign messages.