Incumbent presidents running for re-election always come with built-in advantages: money, time, the stature of the office and the opportunity to define the terms of the race, while an inchoate field of opponents fight among one another.

The Trump campaign is building an organization aimed at capitalizing on all of those advantages, crafting a conventional structure around a candidate whose nature is to buck against it. “There are lots of differences between being part of a bruising primary versus being the incumbent,” said Tim Murtaugh, the campaign communications director. “One of the differences is time. We have a big advantage on the Democrat field in that, and we intend to use it.”…

Mr. Trump is focused on vengeance after the end of the investigation led by the special counsel, Robert S. Mueller III, and his campaign aides are indulging him, attacking the Democrats who have sought to investigate him and the reporters who have written about it. Mr. Trump, whom critics have repeatedly described as “corrupt,” has tried to affix both terms to the news media.

Privately, some Trump advisers acknowledge those attacks may have a shelf life, and that they are deploying them in part to blunt questions about Mr. Trump’s own credibility.