Chris Christie is highly unlikely to win the nomination. The reasons, like his moderate-conservative views and the ethics scandal over bridge traffic in New Jersey, have been summarized elsewhere.But many candidates with little or no chance to win the nomination nonetheless play a big role in presidential primaries, and Mr. Christie could be one of them. He could drain votes from Jeb Bush, widening the opening for Marco Rubio or even improving Scott Walker’s odds to win both Iowa and New Hampshire.

The long-shot candidates who matter tend to be the natural candidates of a large and often dissatisfied faction of a political party, whether as a result of their identity or their stances on the issues. Think of Rick Santorum in 2012, a natural candidate of the evangelical Protestant voters dissatisfied with Mitt Romney. Or Bernie Sanders, the socialist senator running against Hillary Clinton.

Mr. Christie’s path to relevance depends on his becoming a lot more like Mr. Sanders or Mr. Santorum than he would care to admit. He would need to become the natural candidate of the party’s relatively moderate, affluent, secular, blue-state voters.