"I don't need anybody's money," Donald Trump said when he announced his candidacy for president last June. "I'm using my own money. I'm not using lobbyists, I'm not using donors. I don't care. I'm really rich." In fact, the precise degree of Trump's wealth is a matter of some dispute. But as he transitions from the primaries to the general election, Donald Trump may be facing a serious money problem.

The simple reason is that the general election exists on a far different scale than the primaries. Trump has managed something unusual until now: He has run a campaign based largely on free media coverage and big rallies, as opposed to expensive TV ads and campaign staff. According to data collected by the Center for Responsive Politics, as of two weeks ago, Trump had spent $46 million on his campaign, significantly less than the $70 million Ted Cruz spent, not to mention the more than $150 million spent by Hillary Clinton and Bernie Sanders — each.

But the nice thing about the primaries is that they come in sequence, meaning you can concentrate on one state, or a group of states, at a time. Running a campaign spread throughout the whole country takes a much larger organization. A presidential campaign can swell to over 1,000 paid staffers; in 2012, Barack Obama's campaign spent $721 million, while Mitt Romney's spent $449 million. All observers expect the 2016 race to be even more costly. If you think Donald Trump not only has that kind of cash in liquid form but would drop it on his presidential campaign, I've got a line of steaks to sell you.

And Trump is way behind the curve already. While much of that $150 million Clinton has already spent is gone, a lot of it was an investment that she can draw on in the general election, with offices in key states and operatives establishing networks of activists and volunteers who will work during the general. That's not to mention the fact that Clinton has nearly $30 million still in the bank.

She also has a fundraising network a few decades in the making, which she will continue to call on. Trump, on the other hand, seems to have just realized he'll need more money in the general election than he can supply. Raising money, he told an interviewer this Wednesday, is "something we're going to start on right away."

But what about all those super PACs, through which billionaires funnel enormous amounts of money to buy elections? Well ask yourself this: If you were a big Republican donor, how eager would you be to write checks to support the candidacy of Donald Trump, a buffoon who looks like he's going to drag your party down to an epic defeat? Mitt Romney was one thing — he was a guy like you, and he had a shot to win. But Trump?

That's why Charles and David Koch, whose network of like-minded plutocrats had planned to spend nearly a billion dollars helping the Republican nominee get elected, have changed their plans. Now the Kochs say they'll spend the money not on the presidential race but on helping Republicans get elected to Congress. Don't be surprised if other big Republican donors make the same decision. After having flushed a couple hundred million dollars down the toilet trying to defeat Trump in the primaries, why would they open their checkbooks for him now, especially when he looks so likely to lose? It would be a much more effective investment to try to keep Congress in Republican hands so it can restrain President Clinton.

Trump is now going to start asking people for money, which will probably be more than a little uncomfortable for him. And he'll almost certainly find lots of Republican donors unwilling to pony up. It could also dampen the enthusiasm of some of his supporters. You've no doubt heard them quoted in the news saying that they like the fact that he's rich, because among other things he can't be bought and he doesn't have to rely on anyone else to fund his campaign. Once that's no longer true, his wealth may not seem quite so appealing.

If he encounters those difficulties, Trump may decide that it's not a problem if Hillary Clinton outspends him, because he can get so much free media coverage that it'll make up the difference. And it's true that he has been the recipient of more media attention than any candidate in memory; The New York Times estimated the value of all that coverage at $1.9 billion. But that was in a race where it was Trump against a bunch of other candidates. In a one-on-one contest with Clinton, the norm of balance will kick in and she'll likely get at least comparable amounts of coverage as he does.

More importantly, though Trump may believe that there's no such thing as bad publicity, in politics that isn't true. All that coverage helped him defeat his opponents by becoming the choice of more Republican voters than anyone else — in other words, he assembled a plurality of a minority. In the process, however, all his repellent character traits have been on full display, and as much as two-thirds of the public now has an unfavorable opinion of him. So having more voters see him on TV is probably not the thing that will carry Trump to victory.

One can't help but wonder whether Trump even understands how far behind he is, in both money and public esteem. This is a man of almost pathological narcissism, who literally says things like "Everybody loves me." And there's plainly nothing more important to him than for everyone to understand how rich he is. What an irony it would be if he lost in large part because he couldn't put together enough cash to mount a winning campaign.