Here's one instance among many (from this article):
Because let me tell you, if we lose this election, you’re going to have three, four or maybe even five justices (appointed by Democrats) and this country will never, ever recover. It will take centuries to recover.
He says it over and over -- three or four or five judges will be appointed to the Supreme Court by the next President, and we'd better make sure that it's us rather than them who's doing the appointing.
Notice that the context of Trump's warning is always what would happen if the Democrats, i.e. Hillary, were to win. He's not addressing what would or would not happen if he were President.
So how does he get "three or four or five"?
The first is obviously Scalia's successor.
And both Ginsburg and Breyer are getting very long in the tooth, are liberals, were appointed by Hillary's husband, and would probably be OK with retiring while Hillary was President, so that they could be assured of their replacements being hardcore liberals. But getting them to retire is not a guaranteed thing, so this is probably who Trump has in mind when he says "or four or five".
Who are the other two, then? They would fall under what Trump believes is a certain minimum of three (in addition to Scalia's successor). They would have to come as a pair, otherwise Trump would have said "two or three or four or five".
Certainly it would not be the conservatives, since Hillary would not be able to persuade them to retire, and they're not elderly enough for that to be a possibility in the first place. Only Kennedy is old, and nothing links him in a pair with another Justice that would remove both of them together.
That leaves only the liberal appointees, Sotomayor and Kagan, who are linked by having been appointed by Obama. Yet they are not elderly, so they would not be retiring out of senescence.
So would they be removed because they were appointed by an illegitimate President, who was not a natural-born citizen? (Either removed outright or persuaded into early retirement so they can save face.)
When I've read this topic discussed on other sites, the person is usually ecstatic about a would-be President Trump himself proving finally that Obama was not qualified to be President because of his birth status (perhaps using Presidential authority to unseal records), then using that to say YOU'RE FIRED to both of his Supreme Court appointees, and putting two staunch conservatives in their place.
However, Trump has always brought this matter up in the context of "what if Hillary were to win?" He was on the inside of the Establishment for decades, and has many confidantes who are high-ups on the politicians' side (Christie, Giuliani). He keeps issuing the same warning with the same numbers. And if he's choosing that topic as the one to warn or threaten the GOP leaders with, he must be more certain of that than any other threat he could make.
In short, it sounds like Trump knows that Hillary is planning, if she were President, to unseal the relevant records, prove Obama was not qualified for President, hence his choices are null and void, including his Supreme Court appointments. That explains why Trump lumps them in as an inseparable pair, who along with Scalia's successor, would make up a guaranteed minimum of three new appointments under a Hillary administration. The part about "or four or five" refers to the possibility of Hillary persuading Ginsburg and Breyer to retire for the greater liberal good.
Remember that it was Hillary's camp -- not Republicans -- who first brought up the birther and Muslim issues about Obama back in 2008, when he began muscling his way past her royal highness in the primaries. The Clinton camp and the Obama camp have bitterly hated each other ever since. Obama may allow Hillary to be indicted for her email server crimes, and on the campaign trail Bill Clinton has recently started to talk smack about the "awful legacy of the past eight years".
There's no love lost between the two sides, so Hillary's motivation for proving Obama illegitimate is partly revenge for her losing the nomination in 2008. She will get to erase his legacy, and put in her own two liberal Justices who will preside for generations to come.
But also remember that we're talking about one of the most corrupt politicians in world history, so there's going to be that motivation as well. How much do you have to donate to the Clinton Foundation to secure your choice of appointee to the Supreme Court? The appointees themselves would not have enough money to bribe their way in. I mean, if you're a billionaire liberal conspirator like George Soros, what would it be worth to you for Hillary to guarantee your choice of Supreme Court appointment -- two of them, in fact?
That would be in addition to the Scalia replacement, which would only be motivated by corruption and not revenge against Obama. Ditto for the possible replacements of Ginsburg and Breyer. Hillary and Soros, or whoever, give the sitting Justices what they want in order to retire (money, positions, donations to their choice of organization, etc.), and then Hillary collects from Soros to replace them with judges of his choice.
So for both revenge and big bucks, Hillary would prove Obama was illegitimate to begin with. Trump knows this -- and because he keeps using it as a warning to the Republican leaders, they must know it too. For all we laypeople know, it may be the biggest open secret in Washington. Maybe that's why Obama hasn't categorically cleared Hillary of any wrong-doing -- if he feels like she'd get revenge and erase his legacy, he'll just prevent her from getting elected by having her prosecuted while running her campaign.
Still, Trump seems so sure that these "three or four or five" Justices would be appointed no matter which Democrat won, that Hillary must be planning to prove Obama illegitimate no matter what happens to her own campaign. Worst comes to worst, Obama prosecutes her and torpedoes her chances, the Democrats put in Joe Biden or Elizabeth Warren or whoever, and should that Democrat win, Hillary pulls the trigger on the birther issue, and the non-Hillary Democrat President gets another two Justices to appoint.
That suggests that Hillary may already have damning evidence, which she would not need to be President in order to produce. Even sidelined by prosecution, she could still prove her case and erase Obama's legacy out of revenge -- although in that case, she would not get to also enjoy the corruption funds from Soros to appoint the replacements. But if Obama sinks her career, pure cold revenge would be enough of a motive.
I never paid much attention to the Obama birther issue, but it is starting to look more and more real every day now. And whether it's Hillary or Trump who becomes the next President, either way we'll finally have the matter settled in favor of the birthers. We don't need to know what the precise technical evidence might be -- it's enough for us to see Trump repeatedly warning the Republican Establishment by referring to what everyone assumes will be Hillary's "three or four or five" appointments, which can only be achieved if she gets to void Obama's choices automatically.
The good news is that Trump himself will get to make the same number of replacements if he wins, using the same evidence that Hillary knows about, so we'll get even more conservatives onto the Court than if he were only replacing Scalia.