[Here's Anti-Immigrant Opinions are Weakly Held I.]
In his book The Rise and Fall of the Great Powers: Economic Change and Military Conflict from 1500 to 2000 Yale history professor Paul Kennedy makes the case that, historically, great powers have risen to a point where they have become overextended because of their imperial commitments and the expenditures needed to defend them, at which point they have collapsed.
I was reminded of this when I saw the television ad Rep. Tom Tancredo is running in Iowa. (It's getting much more play in the blogosphere than he could ever afford to buy.)
By equating immigrants to terrorists, this leader of the anti-immigrant right is shedding credibility - the coin of the political realm - at a furious pace. His argument just doesn't square with the real world or the common sense judgments good American people make for themselves.
Anti-immigrant opinions have reached their apex. The cartoonish quality of Tancredo's hysteria-mongering presages the fall. See for yourself.