Forgiveness from God is very conditional and reasonable for both a nation and an individual. Also, the Judgment of God was not only on Judah and Jerusalem then, but it is upon every nation that sins against Him including the United States. There are what people call "natural disasters" going on right now with the flooding in Louisiana, but it is really part of the Judgement of God upon a sinning nation. When God judges a nation both the sinners and Christians suffer.
People need to take the Bible very seriously.

Psalm 9:17 KJV
The wicked shall be turned into hell, and all the nations that forget God.