Why Don't We Go Back?

So why has NASA never been back in the last 30 years and why haven't the Russian's been?

As the main driving force was political, once the first landings had been accomplished and the USSR soundly beaten, the government finance started to dry up.  The Apollo missions were incredibly expensive and people were starting to wonder if it was worth it now we knew it was just a dry lifeless rock and that the Russians weren't in the running anymore.   The USSR space program had hit a number of very explosive failures and weren't so keen to go either now.  There's little glory in being second on the moon.  Within a decade or so and the USSR had enough problems running the country and their nuclear reactors to even consider trips to the moon.

The military weren't so bothered either.  The idea of some kind of missile base on the moon was never a consideration.  By the time it took the missiles to reach Earth everything would be over anyway.   What was much more practical was satellites, spy and otherwise, and any military developments could be achieved easier and cheaper in low orbit than on the moon anyway.  So the military preferred the money to be spent on the Shuttles.

That just leaves scientific reasons.  The scientists would love to go back to the moon as there's bound to be lots more to discover.  Unfortunately the scientists aren't in charge of handing out the money.  If you're American ('cos lets face it, they're the only ones who could afford it) and you want to go back to the moon, then tell your politicians that.  They need convincing.