The biggest casualty from the Iowa caucuses is the conventional wisdom.

The conventional wisdom was that Hillary ClintonHillary Diane Rodham Clinton3 ways government can help clean up Twitter Intelligence Democrat: Stop using 'quid pro quo' to describe Trump allegations The Memo: Bloomberg's 2020 moves draw ire from Democrats MORE would be the next president.

Now, the conventional wisdom is that Hillary Clinton will drop out in the next 48 hours.

Last summer, the conventional wisdom was that John McCainJohn Sidney McCainCindy McCain says husband John McCain would be 'disgusted' by state of GOP Meghan McCain to Trump Jr. on 'The View': 'You and your family have hurt a lot of people' Trump Jr. defends father on 'The View': He's 'controversial,' but 'took on the establishment' MORE would drop out of the race.

Now, the conventional wisdom is that he will be the nominee.

The conventional wisdom was that Rudy Giuliani had no chance that to get nomination.

Then, the conventional wisdom was that Rudy Giuliani had no chance to not get the nomination.

Then, the conventional wisdom reverted back to the previous point.

The conventional wisdom was that Mitt Romney would win Iowa and then New Hampshire, and then catapult to the top of the Republican ranks.

After Iowa, the conventional wisdom was that if Romney lost New Hampshire, he was finished.

For most of the year, the conventional wisdom was that Mike Huckabee was not a serious candidate. Now, it’s conventional wisdom that he still doesn’t have shot, even if he wins South Carolina and most of the rest of the South.

The conventional wisdom was that Barack ObamaBarack Hussein ObamaJuan Williams: Honesty, homophobia and Mayor Pete Democrats debate how to defeat Trump: fight or heal 3 ways government can help clean up Twitter MORE was too inexperienced to be a serious presidential contender. Now, most people expect him to be our next president.

It has been the conventional wisdom that the Republican candidate has no chance to win the election. Let me be the first to say that if Obama gets the Democratic nomination, that the new conventional wisdom will be that the Republicans have a very good shot of retaining the White House.