I didn't see 'Wag the Dog' which is why I mentioned 'heard' However, seems like it went from theater to pay TV and videocassette pretty fast. That is usually the sign of a bad movie. In fact, it has gotten more publicity during the Clinton and Sapling administrations due to foreign policy moves during times of domestic criticism than it ever got while in theatrical release.
Box office success is not necessarily the benchmark of a good movie. Just look at some of the mindless crap that does do well in the box office. If that was the real standard than all of these movies made of nothing but car chases and explosions and fist fights would be classics. Of course everyones opinion is different.