No, it’s not time for a pop quiz.

Instead, for the U.S. government and the many companies that provide its weapons and defense systems, the time is coming to start deciding on priorities and coming to grips with how to finance all of the things that need to be done.

Robert Stevens, CEO of Lockheed Martin, said at the Reuters Aerospace and Defense Summit on Tuesday that he expects a vigorous review  of everything the government buys, flies or uses to defend its shores.

Stevens, one of the featured speakers at this year’s gathering in Washington, D.C., said he expects that sometime in 2009 the picking-and-choosing will start — but, fear not, he doesn’t expect a full-scale halt of all military spending.

He does, however, see prioritization and rationalization coming.

The Aero and Defense Summit is the final one of the year. In 2008, Reuters has had 33 summits around the globe and have as many or more planned for 2009. Our previous gathering, Reuters Investment Outlook Summit, provided clients with an excellent look at how to manage through what will certainly be a challenging 2009.