\That may be true; it's hard to say since we haven't had an election between a moderate and a liberal in the US Presidential elections in the last 30 years.
Our previous Republican presidents have all proudly claimed to be conservatives, while sticking the mainly moderate Democrat candidates with the label "liberal". So it may be that a conservative will always win against someone perceived as a liberal.
It's kind of hard to say, since the stated policy goals of the Democrat "liberal" candidates have always been closer to the American mainstream than that of the Republican conservatives. My guess is that the winner will be the one whose swagger causes the bigger boners in the pants of the good ol' boys.
IMO very few people are true Conservative or Liberals across the board. Take for instance Huckabee -- he is obviously a social conservative but his Fiscal policy and actions as Arkansas governor would be considered very Liberal by the current Conservative status quo. Bush also pushed a Conservative social agenda but his administration has spent like a drunken sailor in a whorehouse. Clinton was a social liberal put his foreign policy was quite Conservative.
Liberal and Conservative have simply become catch-phrases for someones social attitudes rather than true political preferences. We have become a nation of one-issue voters and these issues prevent people from looking at the big picture. When someone hears Liberal or Conservative they don't think of Fiscal and Foreign affairs, Budget, Taxation, or the Military - they immediately think of someone's stance on abortion or gay rights.
In this election, Social Conservatives will grudgingly vote for the McCain GOP ticket simply because they understand that failing to do so increases the chances that Obama/Hillary are in the WH.
IMO, the success of the DNC in this election depends on having Obama and Hillary on the DNC ticket. It is very possible they are going to drag each other through the mud to the point the DNC Convention turns into a WWF smack down. It might very well divide the Obama and Clinton camps to the point their supporters do not want to see the other take the WH out of spite. Without a Hillary/Obama ticket, it could spell trouble if the supporters of the loser are so ticked off they are no-shows on election day. Also, if the mud slinging gets bad enough, the loser might very well say 'no-thanks' to a VP offer.
The DNC ticket can implode very quicklky if they are not carefull.
For me, it's another case of having to pick from the lesser of two evils. Slim pickings again. I really am not enthralled with any of the prospects this time around, either DNC or GOP.