What did Donald Trump do today?

He falsely claimed to have saved taxpayers $999,850,000.

In the midst of a joint press appearance with German chancellor Angela Merkel, Trump cut off a reporter's question to tell a confusing story about a funding proposal for a new embassy in Israel, which in his telling would cost a billion dollars. (The United States needs a new embassy because Trump authorized its relocation from Tel Aviv to Jerusalem. America's allies warned against this move because of its potential to disrupt the Israel-Palestine peace negotiations.)

Trump--again, in his own telling--was halfway through his signature when he decided (on his own) to call the U.S. ambassador to Israel. The ambassador told him that an embassy could be built for $150,000 instead. As a result, he said, "instead of in 10 years from now, we can open it up in three months" and at 0.015% of the cost.

The only problem with Trump's story is that it saves no money or time whatsoever. It simply designates an existing consular facility as a temporary embassy while a site can be located and a sufficiently secure embassy built. In fact, this seems to have been the plan all along, since the extraordinary security challenges of building a secure embassy in a city that is a prime target for terrorism or military attacks will take years to overcome.

If Trump ever plans to build a real (and safe) embassy, as he promised he would during the campaign and as president, the billion-dollar costs will still have to be paid.

Why does this matter?

• It's not clear why Trump thinks this story makes him look good.