Personally I think it is very easy for them to switch if they do not agree with extreme liberal policy towards subsidizing many of the social ills we experience today. His policy towards green energy also appears to be very unrealistic and bogus.

Quite frankly none of the candidates have a good idea for the economy so I don not see how that changes anything. Clinton and Obama both support an economic policy based on demand by distributing wealth back to the poor. This is not going to fix anything. Our national savings rate is negative and we are basically shipping away money and capital to china. Adding money into the pockets of the lower class does not increase saving because it goes from the rich (savers) to the poor (spenders). It does not address anything at all.

In order for McCain to justify taxes remaining the same, he would have to cut government spending, which he does not appear to have any intention of doing.

If a candidate were to stand up and say, "Listen. Most of you have been living above your means for years, and now we need to cut back. To address the fiscally irresponsibility of our federal government, I'm going to raise taxes and cut government spending.", they would probably be attacked.