“There are still quite a few combinations here,” said Greg McNeilly, a Republican strategist in Michigan and longtime adviser to Secretary of Education Betsy DeVos. “This guy has an unshakable base, but he has a pretty low ceiling. So that combination has just created this substrata that he has across all states that allows him to be within reach of winning, but suppressed, below it. It’s a really weird dynamic.”

Four years ago, Trump’s prospective map appeared much narrower at this point in the campaign. Exactly half of his general election campaign events were held in just four states: Florida, North Carolina, Ohio, and Pennsylvania.

“We looked at basically six states in 2016 that were in play, and we didn’t know about three of them,” said Whit Ayres, the longtime Republican pollster. “You have double that this year. You have at least a dozen states that could legitimately go either way.”

Much of the map’s fluidity is a function of Trump’s weak standing nationally — forcing Republicans to adopt a defensive posture in states that Trump won easily in 2016.