The Russians didn’t hack into Hillary Clinton’s private e-mail server, as others have reported, according to a very reliable source of mine who has connections with US intelligence agencies.

They didn’t have to.

Clinton was so careless when using her BlackBerry that the Russians stole her password. All Russian President Vladimir Putin’s gang had to do was log into Clinton’s account and read whatever they wanted.

They had to be laughing their butts off. So you can add the Russians to the list of people who know bad and personal things about Clinton that the Democrats will wish remain hidden.

FBI Director James Comey said a few weeks ago that Clinton had been “extremely careless” with her e-mails, but he added that he didn’t think the server she’d been using had been hacked by “hostile actors.”

But Comey also said it was unlikely the FBI would be able to find such evidence if a hacking had occurred. He added, “It is possible that hostile actors gained access to Secretary Clinton’s personal e-mail account.”

Clinton countered by saying that Comey was just speculating about a hacking. “If you go by the evidence, there is no evidence that the system was breached or hacked successfully,” she said.

My source says he’s “absolutely 100 percent sure” on what he told me. “I know it to be fact.”

What’s in any e-mail account? Stuff about your personal life, including embarrassing conversations. In Hillary’s case, speeches and details about the payments. Clinton Foundation secrets. The Russians, I’m told, got it all.

Comey and Clinton could, then, honestly say the server wasn’t hacked. But he never addressed the point — and may not have known — that the Russians had an easier way to get Hillary’s vital information by simply logging in to her account.

So let’s assume the worst — that Putin knows everything that Hillary did for years by having someone sign in under her password and read her mail. What does he do next? He could, of course, release the 20,000 or so e-mails that Clinton thought had been erased and stir up the November election.

Putin is welcome to give them to me. But he’ll probably go the usual route — WikiLeaks.

Or he could hold some back so he can blackmail President Clinton if she wins.

My continuing point is this: The Democrats should pick someone else. Too many people know too many bad things about Hillary. And someone is going to let loose before November.