Standing idly by

'In the end, we will remember not the words of our enemies but the silence of our friends.' - Dr Martin Luther King

It seems to me that many Christians lay the fate and events of the World as a whole on the heads of two beings: namely God or Satan. Of course it is always noticed that whenever something marvellous happens in the World it is attributed to the miracle and love of God. If, however, something horrific or terrible happens it is obviously the work of Satan. I can understand the distinction here as God and Satan are supposed to be on opposite sides of the Good-evil coin.
What I do not understand is the Christians' ease at blaming everything bad on Satan and letting God completely off the hook. I always thought that God was the supreme being and therefore had the power to do anything that he set his mind to. If this is the case then surely this would make God guilty of doing evil through omission. If God is more powerful than Satan and he loves his people so much, then his sitting idly by and doing nothing as Satan runs amok with his evil doings makes God just as responsible for the outcome as his sinister nemesis. If you could stop evil wouldn't you do it? Then why doesn't God? Is it because he can't? Or because he doesn't want to?

'Evil prevails when a few evil men collaborate and good men do nothing'