With Donald Trump’s poll numbers plummeting, the news that he had fired his controversial campaign manager, Corey Lewandowski, was hardly surprising. Photograph by Andrew Harrer / Bloomberg via Getty

These days, American Presidential campaigns are ludicrously long, ludicrously bloated, and ludicrously costly—but the basic principles haven't changed in decades. To win, you first have to put together a majority (or plurality) of primary voters, and then you have to appeal to the country at large.

Donald Trump, who launched his campaign a year ago, turned out to be a much better primary candidate than many people, including possibly he himself, expected. His "blow it all up" message, his direct manner, and the fact that he isn’t a career politician have resonated with disaffected Republican voters across the country. So far, however, Trump has proved to be a truly terrible general-election candidate. Since Ted Cruz dropped out of the race, on May 3rd, Trump has failed to broaden his appeal, and his efforts to launch a national campaign haven't so much imploded as failed to come together at all.

The news on Monday that Trump had fired his controversial campaign manager, Corey Lewandowski, was hardly surprising. With Trump's poll numbers plummeting, and with an organized effort under way to dump him off the G.O.P. ticket at the Party’s Convention in Cleveland, at the end of July, somebody had to be held accountable. Trump being Trump, it wasn't going to be him. He's too mentally fragile to admit he's goofed up. And, in any case, he has long lived by Lord Beaverbrook's maxim: Never apologize, never explain.

Step forward Lewandowski, a brusque, buzz-cut-sporting native of Massachusetts, who is perhaps best known for manhandling a young female reporter, Michelle Fields, at a campaign event in March. Lewandowki's motto was "Let Trump be Trump," and he never got along with the highly paid mercenaries Trump hired late in the primary season to oversee the delegate process. On Monday morning, the Trump campaign issued a statement saying that it was "grateful to Corey for his hard work and dedication and we wish him the best in the future.”

Paul Manafort, a veteran lobbyist and political consultant who is now running Trump's campaign, will doubtless put out the word that Trump understands what a perilous situation he's in and that, from now on, he'll be a more professional, careful, and inclusive candidate. I'll believe it when I see it. Trump appears to be a one-trick pony. In focussing, verbalizing, and mobilizing the political alienation of a certain segment of the American population—one largely, but not exclusively, drawn from the ranks of working-class and middle-class white men—he has no equal. But in appealing to the voters he needs beyond his base—suburban white women and conservative minority voters particularly—he has demonstrated little or no aptitude.

In fact, that's putting it mildly. Seven weeks after becoming the presumptive Republican nominee, Trump still doesn't have a campaign organization worth the name. He's short of money, data, and volunteers to knock on doors. He doesn't even have a proper super PAC to which rich Republicans who can stomach his populist rhetoric could send donations. The Clinton campaign, which only wrapped up the Democratic nomination a couple of weeks ago, has already put out a series of ads attacking Trump's record and portraying Hillary Clinton as a unifier and a steady hand. The Trump campaign has put out nothing. Zilch.

Rather than exploiting his head start to unify the Republican Party and build a formidable campaign apparatus, Trump has been running his mouth, and his Twitter feed, in such an incendiary and counterproductive manner that, at some points in the past few weeks, I have started to wonder whether—consciously or subconsciously—he might be trying to self-destruct before the Convention, so that he doesn't have to go through the humiliation of being beaten badly in the fall. It's an outlandish theory, but how else are we to explain Trump's behavior?

In early May, an old tape turned up of a reporter talking with someone who was pretending to be a spokesman for Trump. Although the voice on the tape was clearly Trump’s, he baldly denied making the call. A week or so later, he said there would be riots in Cleveland if Republicans attempted to deny him the nomination—a statement that earned him a public rebuke from House Speaker Paul Ryan, whose support he was then seeking.

Then came the furor following Trump’s racist remarks about a federal judge, Gonzalo P. Curiel, whom he accused of being biased because of his Mexican heritage. (This despite the fact that Curiel was born and raised in Indiana, and, before being appointed to the federal bench, spent thirteen years prosecuting members of Mexican drug cartels.) After Republicans subjected Trump to a barrage of criticism, and one of them, Senator Mark Kirk, of Illinois, withdrew his endorsement, Trump resorted to a teleprompter for a speech he delivered on June 7th, the day of the California primary. Hey presto, he didn't annoy anybody except the reporters who had to sit through a rote denunciation of the Clintons.

Despite that gesture, though, Trump hadn't learned his lesson. The day after the deadly mass shooting in Orlando, he took to Twitter to draw attention to himself and to exploit the situation for political gain. A day later, he went on television and insinuated that President Obama harbored sympathy for Islamic terrorists. A day after that, during a speech in North Carolina, he claimed that U.S. soldiers in Iraq stole cash intended for reconstruction projects. In the past few months, it has often been said that Trump might be just one big terrorist attack from becoming President. But when just such an awful event happened, he blew it. Anyone with a bit of political nous, let alone a bit of humanity, would have held off for a day or two from making any political comments, out of respect for the victims. Trump blundered in, made himself the story, and prompted yet more criticism from senior Republicans.

It was at this point that I started noticing some people on Twitter suggesting that Trump might be trying to lose. If Trump is on a self-destruct mission, he's carrying it out pretty effectively. According to the latest polls, he is now the least popular Presidential candidate in recent history. In the Real Clear Politics poll average, he's trailing Hillary Clinton nationally by about six percentage points. Politico reckons that the margin is similar in the so-called battleground states. Eying these alarming numbers, and the reluctance of some G.O.P. donors to pony up for a Trump campaign, Republican leaders such as Ryan and Mitch McConnell appear to be giving at least tacit support to the effort to replace him on the ticket.

Despite all this, Trump still has a potential path to victory, albeit a narrow one. It involves shoring up his position in red states such as Arizona and Georgia, where recent polls show Clinton to be competitive; carrying Florida and North Carolina; and blazing through the Rust Belt states of Wisconsin, Michigan, Ohio, and Pennsylvania.

To pull off such a feat, however, Trump would have to put together an electoral coalition that reaches well beyond the angry and the disaffected people who turn up at his rallies, and who voted for him in the primaries. He needs to secure the votes of concerned soccer moms in suburban Detroit, apolitical office managers in Charlotte, and Cuban-Americans in South Florida who have traditionally voted Republican but who may be put off by his rhetoric about Latino immigrants. Even if Trump now puts together a proper campaign organization—and that's a big if—can he adjust his message to draw in those voters who might be attracted to some of the things he says but not to others? Can he draw people who like his attacks on professional politicians and his "America first" rhetoric, say, but who are concerned by his endorsement of religious tests and the stories about Trump University? Does Trump have the political skills to reassure such voters that he has the judgment and character to be President?

Nothing we have seen in the past seven weeks suggests that he does. The problem with the Trump campaign isn't Corey Lewandowski; it's Trump himself.