Strange things happen when people put their faith in politicians. Noted economists have recently discovered the concept "jobs saved". Others have discovered the win-win two-fer of clean environment plus economic recovery from one investment.
Today, it's high-speed rail in Florida. This project will save-or-create jobs. And it will save-or-create clean air and/or global warming relief.
But if serious people can live with the save-or-create idea, then anything goes. In fact, plausibly serious people have one more line of defense. If the save-and-create results (somehow) fall short, then the obvious response is that we just did not push hard enough. Even more stimulus (high-speed rail, "green" jobs, you name it) will surely be the remedy.
There simply is no falsifiability.
UPDATE
Here are some Florida high-speed rail project numbers from Bob Poole.