McCain is the personification of a “conviction” candidate– to his own detriment declining to reverse positions. It is fairly obvious that he has contempt for Romney’s approach– you recall his “even numbered years” crack– in refashioning himself to fit the conservative open niche(open then, not now) in the race. Romney’s repudiation of campaign finance reform and immigration — two favored items for McCain — has of course been particularly galling to McCain. I do not believe they have converged on immigration, at least not judging from the Univision debate. McCain tactically has accepted a border security first approach but is determined when that is all done to allow those still here to come forward and start a path to citizenship. Romney does not.

As for your suggestion, I think it would be interesting to go back to 2002 and see where everyone was and how far they’ve come but I have given up predicting whether that or anythig else would impact voters.