The long exchange between McCain and Romney on global warming is a crucial moment in this debate and campaign:  McCain-Lieberman is a massive regulatory program which would greatly burden the American economy.  It would tax energy in a regressive and lasting way, and as Romney points out, would drive huge numbers of jobs off-shore without measurably reducing greenhouse gas emissions on a global scale.

Conservatives:  "Cap and trade" would be the greatest expansion of the federal regulatory authority in the past half-century.  John McCain's certainty about the causes of global warming and the solutions put him far outside the mainstream of the GOP.

UPDATE: Bravo to Janet Hook for pointing out that when John McCain opposed the Bush tax cuts, he used class warfare rhetoric to explain his votes.

UPDATE:  "No amnesty."  "No special pathway."  Second mention of the Z Visa. Mitt Romney draws a big line between himself and McCain.  Are conservatives watching?

McCain: "We are all in agreement on what we want to do."  That's just not true.  The more the debate stays on immigration, the worse it is for McCain, period.