The equivalent disaster scenario in immigration would go something like this: "Comprehensive" reform passes. The "earned legalization" provisions work as planned--millions of previously undocumented workers become legal Americans. But the untested "enforcement" provisions (point #5) prove no more effective than they have in the past. Legal guest workers enter the country to work, but so do millions of new illegal workers, drawn by the prospect that they too, may some day be considered too numerous to deport and therefore candidates for the next amnesty. The current 12 million illegal immigrants become legal--and soon we have another 12 million illegals. As a result, wages for unskilled, low-income legal American and immigrant workers are depressed. Visible contrasts of wealth and poverty reach near-Latin American proportions in parts of Los Angeles. And the majority of these illegal (and legal) immigrants, like the majority in many parts of the country, are from one nation: Mexico. America for the first time has a potential Quebec problem,** in which a neighboring country has a continuing claim on the loyalties of millions of residents and citizens.
In one sense, this second grand Bush plan failure wouldn't be nearly as disastrous as the first--tens of thousands of people wouldn't die. In another sense, it would be worse. We can retreat from Iraq. We won't be able to retreat from the failure of immigration reform--no "surge" will save us--because it will change who "we" are.
He's right to be worried. Read his 10 points.