Former President Donald Trump has been having some serious sit-down meetings with some significant national leaders, and it's annoying the Biden administration. These kinds of meetings aren't all that unusual during presidential elections, but as usual, Donald Trump is doing this his way:

In less than two months, Trump has hosted Polish President Andrzej Duda, Hungarian Prime Minister Viktor Orban, former Japanese Prime Minister Taro Aso and David Cameron, the former British prime minister who now serves as the U.K.’s foreign secretary. He’s also talked with Saudi Crown Prince Mohammed bin Salman and others by phone.

It’s not unusual for a party nominee to meet with foreign officials — but that’s typically done overseas and with leaders below the level of president or prime minister. Trump has made a show of bringing these dignitaries to his homes — Mar-a-Lago for some, Trump Tower for others — and treating them to some of the trappings of a state visit. That, in particular, has stuck in the craw of some Biden aides, according to three people familiar with the frustrations.

There is an interesting distinction here. Granted Trump is fond of conducting meetings, even high-profile ones, at his Mar-a-Lago estate. That's understandable; as a former President, he still has a Secret Service detail, and, certainly, they would rather keep the former President in surroundings that are more amenable to controlling who comes and goes.

There's a psychological aspect to it as well. It's a matter of optics: These are the leaders of their nations, and they are coming to Trump, instead of vice versa. It's a recognition that while Trump does not wield power, he does wield influence.

It also sends a strong message from the Trump campaign, a theme that Trump has been hitting hard: "We're not done yet."

See Related: More Doom Polls for Biden on His Lapses, Trump Lawfare, and Who Voters Would Be Better Off With 

WATCH: The Ridiculous Hyperbolic Panic of Nicolle Wallace Over What Will Happen When Trump Wins

The biggest factor on this, I think, is that the various nations of the world, as well as their leaders, are as capable as we Americans of looking at the polling - and hedging their bets as to who will be seated at the Resolute Desk in January of 2025. Oh, some of them are less than sanguine about the notion; but then, they also understand that they don't get a vote:

Foreign leaders are also hedging their bets with the circle of aides and advisers around Trump, working through official and unofficial channels to arrange their meetings — when heads of state are not reaching out to the former president directly. After Trump met recently with one top U.S. ally, a diplomat for the country confessed to having at least six contacts offer themselves up as a liaison.

This looks a lot like what an incoming President would be doing. Nobody should be surprised by the fact that this is happening; not only is it not unusual for presidential candidates to meet with foreign officials, but it's also significant that Trump has already had one term in the White House, and right now, betting odds are even of his having an election victory in November.

It's easy to understand why these foreign leaders would want to be laying some groundwork. They can also, by the way, see the sitting President's ongoing physical and mental decline, and it's the obvious conclusion that old Joe Biden isn't going to last much longer. One way or another, they'll be dealing with a new American leader before long.

And the most likely replacement? Donald Trump.