In some respects it depends on where you're hunting. Here in New Mexico, it is against the law to use any light source, even an invisible one! The only exception is hunting raccoon, and even then it requires a special permit. Further, no hunting at night, excluding the aforementioned, is allowed. This, according to the G&F, is to protect farm animals.
If you're on private property, and you have written permission from the "deeded" land owner (no BLM or leased land), you can use almost anything. I use an ATN X-Sight II, 5x20. Most of the time, you do not need a light source if the moon is out, or there is some ambient lighting. In fact, the last rat hunt I went on, didn't require switching to night mode at all! Sort of weird shooting rats, and seeing them in full color!