President Trump attends the FBI National Academy graduation ceremony on Dec. 15, 2017, in Quantico, Va. (AP)

Before Donald Trump announced his presidential candidacy in June 2015, people were telling him he couldn’t win. Well, first they were telling him he wouldn’t even run, and then when he did, they said he couldn’t win the Republican nomination. And then when he did, they told him he couldn’t win the presidency. Each time, Trump publicly insisted he would win; each time, remarkably, he did.

Put another way, there have been in the past two years two occasions on which people who pay a lot of attention to politics told Trump that he couldn’t win and then Trump proved them wrong. During the campaign, his insistence that he could emerge victorious seemed mostly like bluster (in part because it seemed so far-fetched), but Trump would be forgiven if he thinks he has a better sense of electoral politics than the experts. He wanted to go out and hammer Hillary Clinton and he did it and he won and there’s all the proof he needs.

The problem, of course, is that the two races Trump won were abnormal races. The first had 17 Republican candidates of various pedigrees, a split field that let Trump consolidate the immigration vote to build a larger core base than his opponents. In the general election, he faced off against the second-least-popular presidential candidate in modern history, trailing only a guy named Donald Trump. And, despite that, Trump received fewer votes.

All of that context is useful when considering how Trump approaches the 2018 midterm elections.

Over the weekend, the New York Times reported that Trump seems blasé about his party’s chances in November. Even though Democrats have consistently made double-digit gains against Republicans in special elections over the past 18 months, Trump “is privately rejecting the growing consensus among Republican leaders that they may lose the House and possibly the Senate in November,” the paper reports. Told at a dinner earlier this month that the Republicans were likely to lose the House, Trump offered a curt, “That’s not going to happen.”

How is he so confident? One adviser told the Times that Trump dismisses the opinions of party leaders specifically for the reasons above: “He doesn’t think that’s how you win elections because that’s not how he won his election.”

Right. Fair enough. But the Republicans have majorities in the House and the Senate because of the way Senate Majority Leader Mitch McConnell (R-Ky.) et al. ran those elections — and no one is on Capitol Hill after having received fewer votes than his or her opponent.

Trump also seems to think that he can divert the results of the election through sheer force of will. That’s obvious in his recent tweets about Sen. Jon Tester (D-Mont.).

Tester’s tenure in the Senate has been largely unremarkable, as befits a Democrat from a deep-red state. But his role in helping raise awareness of the allegations against Ronny L. Jackson, Trump’s former nominee to run the Department of Veterans Affairs, earned him a special place on Trump’s target list. Tester should resign, Trump argued Saturday, an assertion that seems to have carried little weight with the senator.

Trump no doubt knows that Tester isn’t going to resign. His goal, in case it needed to be spelled out, is to Clintonize Tester, battering him with negative assertions of various stripes (see Monday night’s) and hoping that those individual anchors are enough to pull Tester down. Why care about a senator from a state that’s only two-thirds the population of the Bronx? Because Montana is winnable for the Republicans — and picking up one Senate seat would make it very tricky for the Democrats to seize the majority.

The disparagement of Tester as uniquely to blame for Jackson doesn’t hold up. On Monday night, CNN reported that concerns about Jackson were not all “phony Democrat charges”: Vice President Pence’s personal doctor raised questions about Jackson, too. When the allegations were first made public, Tester was joined in releasing a statement about Jackson by Sen. Johnny Isakson (R-Ga.). But neither Isakson nor Pence’s doctor is on the ballot in a state the Republican won in November, so they avoid the spotlight.

Such niceties as accuracy, though, have never been limiting factors in Trump’s attacks. Clinton faced a barrage of critiques from Trump, many or most inaccurate or false. The lesson Trump learned, though, was that this was a way to beat an opponent.

It didn’t always work in prior special elections. During the special election in Georgia’s 6th Congressional District, Trump disparaged Democrat Jon Ossoff, who, he said, was “VERY weak on crime” and “wants higher taxes.” Ossoff lost, in part because his special election arrived too early on the Democratic wave. But this may have suggested to Trump that the process could work.

In Alabama, it didn’t.

It won’t always, of course, if it ever does at all. But November also has another down side: Not only are Republicans not all running against someone as unpopular as Hillary Clinton, but they’re all running at once. Unless the last week of the campaign is simply a barrage of 30 tweets a day disparaging Lyin’ So-and-So or Crooked Whoever — which it might be — it’s hard to see how Trump thinks that his personal pressure can hold the House and the Senate.

Politicians are almost always superstitious. They run for office fairly infrequently and tend to stick to whatever worked last time. In Trump’s case, his familiarity with how he won election isn’t only his personal experience, it’s probably the only significant experience he had with politicking. And despite the experts saying he’d lose, he didn’t. So why would he change his tactics now?

The answer, of course, is that his tactics were a fluke and, just to lay it out there, that he has never won a head-to-head popular-vote contest against a Democrat. Imagine a circumstance in which the guy who lost a governor’s race went around telling his party that it was completely wrong about how it could win upcoming races. Odds are he would get some pushback.

Whatever pushback Trump gets, it doesn’t seem to be convincing him that he’s wrong. But, then, what ever has?