Jim - according the Temple Institute and many Jewish supporters, the 3rd Temple can be built in a very, very short time. Some even say a matter of weeks. The materials have already been gathered. The implements are all ready. The red heifers are in their stables. The altar has already been dedicated (and that was a public ceremony). The priests, who have their lineage traced back to Aaron, are already trained and outfitted.
In ancient times, the temple construction took years and decades.
It won't be that way this time. Not only can modern construction race forward, the Jews are vastly aware that a long, drawn out building schedule will be subject to international pressure, political second guessing, and Muslim terrorism.
They will sprint towards its completion. It doesn't even have to be as grand or elaborate as the 2nd Temple. It simply must satisfy the requirements of the Torah.
