[PA Engineer]

The government has no authority to declare war on an ideology.

I disagree. Nazism was an ideology. The US instituted a denazification program at the end of the war. Islam really is the same coin and it's current form was rooted in the Nazi past. Just google the Mufti of Jerusalem and the history of the Baathist party. Many of Sadam's loyalists are now high up in ISIS.

[MamaTexan]

But they declared war on the countries that practiced it, not the ideology itself.