The campaign also presented new internal polling data from New Hampshire. The data found that terrorism and national security are the top issues there and that, according to an aide, “There are half a dozen people within the margin of error competing for second place in New Hampshire, and Governor Bush is very strongly positioned with the best ground game in the state.”

The general Bush pitch hinges on restoring a traditional framework to an election in which — so far, at least — the traditional rules of politics have ceased to apply, and where unconventional outsiders like Donald J. Trump have ridden a frenzy of visceral voter anger to the top of the polls.

Bush supporters argue that voters in Iowa and New Hampshire decide late, and that historically voters ultimately settle on someone more like Mr. Bush, a moderate candidate with a proven record. Mr. Bush, they add, has both the money (his “super PAC” has raised over $100 million) and the organization to stay in the race until the field becomes less crowded, at which point they hope Mr. Bush will fare better.

“If you go back to the Howard Dean days or the Gary Hart days or the Ted Kennedy days, and in our party you can do the same, the only conclusion you can reach is that those at the top of the heap polling-wise are never at the top of the heap when the real races begin,” Al Cardenas, a Bush adviser and friend who did not attend the event, said by phone.