This is a foretaste of why McCain would be more likely to get an amnesty through Congress than Obama:
But another reason for the shift is to avoid the perception of the party rank and file and those running for the first time openly questioning their presumed leader on such a visceral topic.
Downplaying illegal immigration on the campaign trail leaves House Republican incumbents and candidates in a tight spot. On one hand, they are trying to win over a smaller group of voters, and depending on where the district is, illegal immigration could be a hot topic. But if they are too vocal on the issue, they could be seen as challenging McCain, who was elected to the Senate by a much larger and less parochial group of voters but could be hurt in the presidential election by public clashes with his party.