April 23, 2008 -- Remember all those predictions about how the Democratic winner in Iowa would slingshot toward the nomination with a ton of momentum at his or her back? And what about all that focus on New Hampshire? Or Super Tuesday becoming a general election-like battle for states?
If your political GPS tells you we're well beyond the battle for early state momentum it's dead on. Welcome to the world of delegates.
So, How Do They Win?
Unlike November's winner-take-all system of electoral votes, Super Tuesday, the Feb. 5 nationwide battle for delegates, was largely proportional, leaving the Democratic contest split while propelling Sen. John McCain, R-Ariz., toward the Republican nomination.
Following Super Tuesday, Sen. Barack Obama, D-Ill., went on an impressive 10-0 run against rival Sen. Hillary Clinton, D-N.Y., which was only broken by critical Clinton wins in Texas and Ohio on March 4 and Pennsylvania on April 22.
On both sides of the aisle, candidates have to win a simple majority of delegates to secure the nomination. That is, half the total convention delegates plus one.
For Democrats, that magic number is 2,025 out of 4,048 total delegates; for Republicans, it's 1,191 out of 2,380 delegates.
In previous cycles, the combination of early momentum and candidate withdrawals allowed the nomination to be effectively sewn up before the candidate hit the actual magic number of needed delegates.
But this election has been like no other -- defying expectations and countering conventional wisdom at almost every turn.
It's Their Party, They'll Play How They Want To
The two parties differ in their rules for defining and allocating delegates, and perhaps it's no surprise that the two parties' philosophies on this process reflect their overall political philosophies.
The Democratic National Committee oversees its party's delegate process, acting as a central authority for the 50 states and territories, and applying the same standards and rules across the board to each delegate race.
Unlike the GOP, there are no winner-take-all states on the Democratic side. Democrats accumulate delegates proportionally, using the popular vote from either the state or district contests.
Adopting the states' rights attitude central to its party, the Republican National Committee gives considerable leeway to the state parties to determine how they select delegates and award them to candidates.
GOP races vary state by state, but for most of Super Tuesday's 21 contests -- which all but locked up the nomination for McCain -- winners were accumulated in a winner-take-all manner.
How the Democrats Do It
Democratic delegates divide into two groups: pledged delegates and superdelegates.
Pledged delegates are any of the 3,253 Democratic delegates awarded through voting in state primaries and caucuses. To win them, Democratic candidates must capture at least 15 percent of a statewide vote or 15 percent of the vote within a congressional district.
As a result, candidates are likely to push in every state -- especially delegate-rich ones -- because there is always the possibility of picking up some delegates and blunting a clean victory for the statewide winner.
In Nevada, Barack Obama was able to accumulate an estimated 13 delegates compared with Hillary Clinton's estimated 12 despite her 6-point victory.
What is a 'Superdelegate'?
In addition to the pledged delegates, 795 "superdelegates" get to act as free agents and can select whichever candidate they wish for the nomination.
Superdelegates are Democratic members of Congress, governors, former Democratic presidents, as well as state and national party leaders.
They are not bound to their candidate based on the primary or caucus results from their state, and there is no formal process to win them, though campaigns put forth considerable efforts to gain their formal support.
The 795 Democratic superdelegates account for nearly 40 percent of the 2,025 total needed to win the Democratic nomination.
Superdelegates are under no obligation to publicly declare candidate support, which makes counting them an inexact science.
How the Republicans Do It
Without overarching party rules, the GOP gives considerable flexibility to state parties in determining how they allocate their delegates. There are three main ways that Republican candidates win delegates: winner-take-all, proportional and by congressional district.
In most a majority of Republican contests, the winner took all state delegates no matter how narrow the margin of victory in the popular vote. In other words, the candidate who won the popular vote won every delegate from the state.
Sen. McCain won several winner-take-all states including Arizona, New York and New Jersey; so, even though his rivals, former governors Mike Huckabee and Mitt Romney won votes, they didn't win any delegates.
But other GOP contests, such as Massachusetts, follow a model similar to that of the Democrats in which delegates are awarded proportionally based on the statewide vote.
Romney won Massachusetts on Super Tuesday but because the state allocates delegates proportionally, McCain won a share of the delegate trove as well.
The remaining states use a combination of winner take all and proportional but divides the state by congressional district.
A candidate wins three delegates from each congressional district based on winning the popular vote within that congressional district.
For example, California, with its 170 delegates at stake, looks like a delegate jackpot.
Given the state's plan for delegate allocation, a narrow win in the statewide vote count does not mean 170 delegates in a candidate's pocket. Instead, they are looking to win in the most congressional districts.
Unlike the Democrats, the Republicans do not have superdelegates.
Some Republican delegates are distinguished as "unpledged" but are not always free agents who are unbound to the state vote on the Democratic side.
Bad States Get Punished
In 2007, both parties sanctioned states for moving their nominating contests earlier in the calendar.
The Republican National Committee took away half of the delegate counts for Wyoming, New Hampshire, Michigan, South Carolina and Florida for scheduling their primaries before Feb. 5, 2008.
The Democratic National Committee stripped Michigan and Florida of all of their delegates for holding primaries before Feb. 5.
Superdelegates who pledged their support to Democratic candidates other than Obama or Clinton before they dropped out of the race can switch their support to another candidate or can remain committed to their first pick until the convention in the summer.
ABC News' David Chalian and Talal Alkhatib contributed to this report.