The Conservative movement is an abysmal failure. Very few want a continuation of the Bush Presidency, yet this is EXACTLY what McCain promises. There is no reason to fear the "tax and spend liberal" label when the so-called conservatives have spent us down the drain while relieving corporate giants and the super-rich of their legitimate duty to support that spending. In 8 years our country has gone from a vibrant economy with a budget surplus to an economy in free-fall with the biggest deficit in the history of our nation. Wars for oil (McCain admits it) are a terrible misuse of American power. The hatred of science and the attendant reduction in our prowess in this arena is devastating to our future. Failure to address climate change, environmental collapse, denial of evolution and failure to take advantage of stem cell research can all be laid directly on the conservatives.
Now, some Liberal notions have been shown not to work and we have to recognize this and distance the movement from the bad ideas of Liberalism. We have to include the welfare state and insisting on cultural relativism among these failures.
But Liberalism is a great notion, with many winning ideas and Obama leads that movement. Unless you believe that Obama has hypnotized those of us who support him and that we really are "Obamabots" then you have to admit that the reason so many Democrats found him preferable to the other alternatives is that he is more liberal. Certainly much of HRC's downfall centers in the fact that she ran away from her liberal base - in the DEMOCRATIC primaries! She completely misjudged how enraged liberals are with the conservative movement.
All Obama needs to do is highlight the many failures of the Conservative movement and people will flock back to Liberalism. To paraphrase the conservative icon Reagan - are you better off than you were 8 years ago? I would wager that at least 60% will say "not at all". And some will cry out that we don't really KNOW what Obama will do with Iran, for instance, but we can say - "we have a good idea and we DO KNOW what McCain would continue doing and we don't want to go there".
There is no more egalitarian political concept than that of Liberalism. If we are to be the America of the Constitution (that the Conservatives have worked at destroying) then Liberalism is the best way to get there. So stop telling people you are a "progressive" and proudly admit to being a Liberal.