One quirk of the American political system is that a candidate can win a primary with a much narrower slice of the electorate than he’d need to win a general election. Donald Trump claimed 45 percent of the vote in Republican primaries and caucuses this year, about 14 million votes. That’s a healthy total as these things go: the highest number of votes ever received by a Republican in the primaries. But Trump will need four or five times as many votes — perhaps 65 million — to win in November. His primary voters are just a drop in the bucket.

All presidential candidates face some version of this problem. But most make at least some effort to expand beyond their base and build a majority coalition. Trump hasn’t — and he has his work cut out for him like no nominee in history. Trump’s decision this week to make Stephen Bannon of the combative, anti-establishment website Breitbart News his campaign’s chief executive suggests that he’s moving in the opposite direction.

In January, even as he stood atop Republican primary polls, Trump was exceptionally unpopular with general election voters. At that time, Trump had a 33 percent favorable rating and a 58 percent unfavorable rating with the general electorate. Today? His numbers are even worse. His favorability rating is just 32 percent, according to the HuffPost Pollster aggregate, while his unfavorable rating has risen to 65 percent.

Trump is helped by the fact that Hillary Clinton might be the second-most-unpopular nominee ever, after Trump. But still, remarkably few Americans are willing to commit to voting for Trump. In the table below, I’ve listed every poll from a 2012 swing state taken since the conventions. On average, Trump has just 37 percent of the vote in these polls (Clinton has 44 percent). That puts him on par with Barry Goldwater and George McGovern, who each got 38 percent of the vote in their respective landslide defeats of 1964 and 1972.

STATE POLLSTER TRUMP CLINTON JOHNSON Colorado Marist College 29% 41% 15% Virginia Marist College 31 43 12 New Hampshire Vox Populi Communications 31 41 11 Michigan Glengariff Group 32 41 8 New Hampshire MassINC Polling Group 32 47 8 Michigan EPIC-MRA 32 43 8 Michigan Mitchell Research 33 44 9 Colorado Quinnipiac University 33 41 16 Virginia Quinnipiac University 34 45 11 Wisconsin Marquette University 34 47 9 Ohio Marist College 35 39 12 Iowa Marist College 35 35 12 Pennsylvania Franklin & Marshall College 36 49 5 Pennsylvania Marist College 36 45 9 Florida Marist College 36 41 9 North Carolina Marist College 36 45 9 New Hampshire YouGov 36 45 5 Pennsylvania Susquehanna Polling & Research 37 46 7 Virginia YouGov 37 49 7 Iowa Suffolk University 37 36 6 New Hampshire Public Policy Polling 37 50 — Iowa Quinnipiac University 39 41 12 Florida Suffolk University 39 43 4 Pennsylvania Quinnipiac University 39 48 7 Virginia The Washington Post 39 46 9 Florida Monmouth University 39 48 6 Nevada Rasmussen Reports 40 41 10 Florida YouGov 40 45 5 Nevada YouGov 41 43 4 North Carolina Public Policy Polling 41 43 7 Pennsylvania Public Policy Polling 42 45 4 Ohio Quinnipiac University 42 44 8 Florida Quinnipiac University 43 43 7 Florida Public Policy Polling 43 46 — Florida Opinion Savvy 44 45 6 North Carolina SurveyUSA 46 42 6 Average 37 44 8 Trump is stuck in the 30s in swing state polls

Trump will probably finish with more than 37 percent by picking off some undecided and third-party voters. Still, with almost two-thirds of voters holding an unfavorable view of Trump, it’s not clear how many more people he can rally to his side without a big change in tone and message.

So it’s not surprising that Trump has undertaken a major shakeup of his campaign, hiring Bannon and promoting the pollster Kellyanne Conway. Campaign Chairman Paul Manafort has effectively been demoted. But rather than make a much-expected “pivot” toward general election voters — as Manafort had reportedly been pushing for — the new plan is to “let Trump be Trump,” doubling down on the strategies that Trump used to win the nomination, including an emphasis on nationalism, populism and “brutal fights with Clinton”:

Huge rallies. Gloves off. Brutal fights with Clinton. Heavy emphasis on nationalism and populism. That's the Bannon strategy. — Robert Costa (@costareports) August 17, 2016

If you trust the polls, this seems like a fundamental strategic error. Trump is running worse than Mitt Romney among almost all demographic groups; white men without a college degree are the most prominent exception. But there aren’t enough of those men to form a majority or really even to come all that close.

How do we know that the rest of the electorate isn’t craving a Trumpier Trump? Because in contrast to the primaries, the general election has followed a fairly predictable course. Incidents that people expected to hurt Clinton’s polling numbers, such as the FBI’s repudiation of her use of a private email server as secretary of state, in fact hurt them. The same is true for Trump. Voters strongly disapproved of Trump’s criticism of Gonzalo Curiel, the judge in the Trump University lawsuit, and his later criticism of Khizr and Ghazala Kahn, the parents of a Muslim-American soldier killed in action, and these incidents were associated with declines for Trump in the polls. And voters continue to doubt whether Trump has a presidential temperament, a vulnerability the Clinton campaign has continuously exploited in advertisements and speeches.

What’s more, Trump already doubled down on Trumpism at the Republican convention, with a disorganized program and gloomy acceptance speech full of nationalist and populist themes. The result was a convention that left most voters with a worse impression of Trump and the Republican Party. Clinton went from having roughly a 3 percentage point lead just before the conventions to more like a 7 or 8 point lead just afterward, and her advantage has held roughly steady ever since. August is still too soon to declare any presidential campaign over. But Trump and his acolytes seem to be in profound denial about the narrowness of their appeal.